The Biggest Boom-or-Bust 2023-24 MLB Free Agents

Sometimes, MLB teams sign the exact free agent they need, getting the final piece of a World Series puzzle who pans out even better than their wildest dreams.

Other times, free agents sign massive contracts and turn into square pegs being shoved into round holes on teams going nowhere fast.

They might go boom. They might go bust. And many of this year's most noteworthy free agents seem to have limitless potential in both directions.

Two weeks ago, MLB Trade Rumors put out its list of the top 50 free agents, ranked in descending order of what it perceives to be their projected contract size. It ended up with 16 players projected for at least $45 million, eight of them north of $110 million. And considering it had Aaron Nola at 6/$150M before he signed a 7/$172M deal to remain in Philadelphia, it's off to a pretty good start with those projections.

Whether those 16 players will actually be worth those contracts is a different conversation altogether, though, and we've nominated the eight members of that club who have the biggest boom-or-bust potential.

Just like MLBTR, we've ranked these boom-or-bust players by projected contract size. But if we had based this on how uncomfortable we would be with our favorite team signing the player to the projected contract, you better believe Cody Bellinger at 12/$264M would be No. 1 on the list. If he gets a Xander Bogaerts-type deal one year after the Dodgers told him to kick rocks, mercy.

Age: 31

2023 Stats: .250/.341/.512, 36 HR, 75 RBI, 1.8 bWAR

MLB Trade Rumors Contract Projection: Three years, $45 million

Why He Could Go Boom

Jorge Soler has a ton of power in his bat.

He led the AL with 48 home runs in 2019. After getting traded to Atlanta at the 2021 deadline, he had 14 round-trippers in 55 games (plus three more in the World Series). And this past season, he hit 36 home runs for the Marlins—with 12 in May and 10 in August.

Though he's not as consistently powerful as a Pete Alonso, Aaron Judge or Shohei Ohtani, Soler is a certified slugger with 162-game paces of 38 HR and 92 RBI over the past half-decade.

Why He Could Go Bust

Despite the home runs, Soler doesn't provide much value.

From 2020-22, he was worth a grand total of 0.5 bWAR.

He's more reliable than, say, Joey Gallo, but Soler is a career .243 hitter who whiffs in more than a quarter of his trips to the plate. He has also been primarily a designated hitter over the past five years, and he is a considerably below-average corner outfielder when asked to wear a glove.

Basically, he's Kyle Schwarber lite, but more susceptible to injury and less likely to draw walks.

On a three-year deal at $15 million a pop, you might get one year in which he's worth it and two in which he painfully is not.

Age: 29 (30 on Friday)

2023 Stats: .251/.336/.471, 22 HR, 70 RBI, 8 SB, 2.9 bWAR

MLB Trade Rumors Contract Projection: Four years, $70 million

Why He Could Go Boom

Though his initial contract year (2022) was a major disappointment, Jeimer Candelario had a solid four-year run from Detroit to Washington to Chicago. His overall value added on offense since the beginning of 2020 is on par with that of Sean Murphy, Anthony Rizzo or Willy Adames.

And when he was hot this past season, he was an inferno.

From May 15 through June 2, there was a 16-game stretch in which he hit .410 with 13 extra-base hits. And in his first nine games after getting traded to the Cubs, he hit .485.

There's also the positional scarcity and flexibility. While he's no Gold Glover at the hot corner, he is plenty respectable at a challenging spot on the field. Candelario can play first base, too, which means he would be a welcome addition to just about any team.

Why He Could Go Bust

While the hot streaks are tantalizing, the cold streaks are infuriating.

After the incredible start in Chicago, Candelario hit .150 over his final 31 games of 2023. For the 21 games prior to his red-hot stretch this past spring, he had a .143 batting average. And this comes after he spent just about the entire 2022 season trying to snap out of a cold spell.

Per Baseball Savant, he has hit .200 or worse against breaking balls (slider, sweeper or curve) in each of the past six seasons. Opponents seem to have finally noticed, too, throwing him breaking balls 33 percent of the time last season. Also, his expected slugging percentage for 2023 (.405) was significantly below where he actually finished the season (.471).

Candelario has never been an All-Star, but he's going to get paid like a top-15, maybe even top-10 third baseman, if only because the list of hitters in this free-agent class gets rough in a hurry after Shohei Ohtani, Cody Bellinger and Matt Chapman.

Age: 30

2023 Stats: 152.2 IP, 3.30 ERA, 3.66 FIP, 1.15 WHIP, 9.1 K/9, 3.5 bWAR

MLB Trade Rumors Contract Projection: Four years, $82 million

Why He Could Go Boom

Eduardo Rodriguez had a breakthrough year in 2023, particularly early on.

At the end of May, the 30-year-old had a 2.13 ERA, going at least seven scoreless innings four times in the span of five starts. And despite missing more than a month with a finger tendon injury, he made eight more quality starts over the final three months, finishing the year as Detroit's most valuable player.

After allowing at least 8.3 H/9 and 1.0 HR/9 (but never drastically more in either category) in each of his previous seven seasons, Rodriguez allowed 7.5 and 0.9, respectively, and simply looked the part of a guy who finally put it all together.

Why He Could Go Bust

Rodriguez has been above replacement level in every season of his career, but usually not by much.

This year was the first time he finished with an ERA of 3.80 or better, and he still had a 3.66 FIP and a 4.06 xFIP.

While his situation wasn't quite as drastic as Tyler Anderson and Martín Pérez becoming All-Stars out of nowhere in their early 30s in 2022, both of those pitchers returning right back to "barely replacement level" in 2023 does feel like a cautionary tale for Rodriguez's prospective suitors.

Moreover, durability has been an issue for Rodriguez, who has logged enough innings to qualify for an ERA title just once (2019) in his eight-year career. The Tigers signed him two years ago to be their ace, and he only managed to make 43 starts between 2022-23.

Age: 30

2023 Stats: .240/.330/.424, 17 HR, 54 RBI, 4 SB, 4.4 bWAR

MLB Trade Rumors Contract Projection: Six years, $150 million

Why He Could Go Boom

Nolan Arenado is (or at least used to be) a bit better, but Matt Chapman is easily one of the two best defensive third basemen in the majors today. He has won the Gold Glove in four of the past five full seasons, and he was, arguably, robbed in 2022 when it went to Baltimore's Ramón Urías instead.

And Chapman can go boom with his bat, hitting 155 home runs since his debut in 2017. That's almost as many as Juan Soto (160), albeit with Chapman making about 200 more plate appearances than the Padres star has.

Chapman has yet to earn a Silver Slugger to go with his many Gold Gloves, but he has hit at least 24 home runs in four different seasons.

Why He Could Go Bust

Though he does have a good amount of pop in his bat, Chapman is a career .240 hitter who routinely goes through painfully long cold spells at the plate.

After finishing this past April at .384/.465/.687, he hit .205/.298/.361 the rest of the way.

The previous year, he had a ridiculously hot stretch in July, hitting .386/.469/.829 for 20 games. He proceeded to triple-slash .196/.320/.353 over his final 59 games.

And that's the known concern.

The unknown is when the 30-year-old's two-time Platinum Glove will start to noticeably decline.

He did win a Gold Glove this past season, but he committed twice as many fielding errors (six) in 2023 as he did from 2020-22 combined (three). Moreover, both his UZR/150 and RF/9 were a good bit lower in 2022 and 2023 in Toronto than they were for his five years in Oakland, suggesting that his range already isn't quite what it once was.

Even if he just slips from "elite" to "well above-average" on defense, $25 million per year for a .240 hitter could get painful.

Age: 30 (31 on December 4)

2023 Stats: 180.0 IP, 2.25 ERA, 3.44 FIP, 1.19 WHIP, 11.7 K/9, 6.0 bWAR

MLB Trade Rumors Contract Projection: Seven years, $200 million

Why He Could Go Boom

Among pitchers to log at least 500 innings since the beginning of 2018, only Jacob deGrom and Gerrit Cole have a higher strikeout rate than Blake Snell's mark of 11.7.

"Snellzilla" has been consistently dominant in that regard, finishing each of the past six seasons at or above 11.0 K/9.

He won the AL Cy Young in 2018 and the NL Cy Young in 2023, leading the league in both ERA and H/9 in each of those seasons. And even in the less dominant years in between, he's a top-notch source of strikeouts who typically keeps home runs to a minimum.

Why He Could Go Bust

Among pitchers to log at least 500 innings since the beginning of 2018, no one has walked a higher percentage of batters faced than Snell's mark of 10.8.

He led the majors with 99 walks this past season—none of which were intentional.

And though those 2018 and 2023 campaigns were masterful, for the four years in between, Snell had a pedestrian 3.85 ERA and 1.26 WHIP while logging just 413.2 innings pitched—compared to eight much healthier pitchers who tossed at least 200 more innings than that.

To sign Snell, you have no choice but to pay the premium that comes with a two-time Cy Young winner fresh off one of the best seasons of his career. But his recent history suggests there's a good chance you're going to get more than a couple of walk-heavy, injury-plagued seasons.

Age: 25

2023 Stats: 171.0 IP, 1.16 ERA, 0.86 WHIP, 9.3 K/9

MLB Trade Rumors Contract Projection: Nine years, $225 million

Why He Could Go Boom

Yoshinobu Yamamoto has been nothing short of brilliant over the past seven seasons for the Orix Buffaloes.

As an 18-year-old rookie in 2017, he logged 57.1 innings with a 2.35 ERA and a 1.06 WHIP, and he seems to have just gotten better with each passing year since then. For his career, he's at a 1.72 ERA, a 0.92 WHIP and a 9.2 K/9 in a little under 1,000 innings pitched.

For sake of comparison, Yu Darvish had marks of 1.99, 0.98 and 8.9, respectively, when he entered MLB at the same age during the 2011-12 offseason, and he is now a five-time All-Star.

Why He Could Go Bust

Though things have worked out quite well for Darvish—and much more recently for Kodai Senga—the NPB-to-MLB transition isn't always seamless.

Through five seasons, Yusei Kikuchi has a 4.71 ERA. Kenta Maeda never quite developed into an All-Star. And there are plenty of former names such as Tomo Ohka, Kaz Ishii, Daisuke Matsuzaka and Hideki Irabu who were serviceable pitchers but never All-Stars.

But if this contract projection is close to accurate, Yamamoto is going to start out as one of the 15 or so highest-paid pitchers in the majors, and on one of the longest deals we've ever seen a pitcher get.

He might be worth it, because his curveball is downright lethal right now.

Then again, so was Barry Zito's once upon a time.

Age: 28

2023 Stats: .307/.356/.525, 26 HR, 97 RBI, 20 SB, 4.4 bWAR

MLB Trade Rumors Contract Projection: 12 years, $264 million

Why He Could Go Boom

At his peaks, Cody Bellinger has been some kind of special.

He unanimously won NL Rookie of the Year as a 21-year-old in 2017. He won the NL MVP and a Gold Glove in 2019. And despite missing a month of action with a knee injury, he just had the best non-MVP season of his career.

From 2017-19, he homered at a 162-game pace of 40. He was on pace for around 32 this year, even though it took a while after the injury to get his power swing back.

The flexibility on defense is a nice perk, too. Bellinger was primarily a right fielder when he won his Gold Glove, but he can play any of the outfield positions, plus first base. While that doesn't much affect his ability to be a boom of a signing, it could help his new team from a roster-building perspective.

Why He Could Go Bust

At his valleys, Bellinger has been virtually unplayable.

From 2020-22, he hit .203 and slugged .376, after which the Dodgers decided to non-tender the former MVP rather than bring him back for his final season before hitting free agency.

And even though he bounced back in a big way this past season, there are understandable concerns about his staying power fresh off both the highest BABIP and lowest hard hit percentage of his career. He simply did not hit fastballs as well in 2023 as he did early in his career.

Also, 12 years? Seriously?

It's one thing to make that type of long-term investment in a 21-year-old who hasn't even remotely approached his peak in terms of potential or earning power, but $22 million per year for more than a decade on a guy who struggled in three of the past four seasons would be ridiculous.

Age: 29

2023 Stats: .304/.412/.654, 44 HR, 95 RBI, 20 SB; 132.0 IP, 3.14 ERA, 4.00 FIP, 1.06 WHIP, 11.4 K/9, 10.0 bWAR

MLB Trade Rumors Contract Projection: 12 years, $528 million

Why He Could Go Boom

I mean, it's Shohei Ohtani.

He's a generational talent who has already won a pair of AL MVP awards. The only reason he isn't currently riding a three-peat is because Aaron Judge set an American League record with 62 home runs in 2022—and Ohtani still got a pair of first-place votes for MVP that year.

Over the past three seasons, he has a .964 OPS at the plate and a .197 batting average against on the mound. Among qualified hitters, only Aaron Judge (1.017) has Ohtani beat in the former. And among qualified pitchers, only Freddy Peralta (.189) has him beat in the latter.

Why He Could Go Bust

I mean, $528 million is a colossal investment.

Tampa Bay's combined opening-day payroll for the past eight seasons is only $526 million.

We'll see what the number actually ends up being, but that estimate is $44 million per year, all the way through the season in which he'll turn 42 years old.

Feel free to ask the Detroit Tigers how quickly you can regret making a two-time MVP one of the highest-paid players of all time. And that Miguel Cabrera contract was only for eight years at $31 million per season. This projection is 50 percent longer and almost 50 percent more on an annual basis.

Plus, we already know he won't pitch in 2024, so you're accepting that you're only getting half of the Ohtani experience for the first year, hoping for the full package beginning in 2025 and praying that he's able to maintain an MVP level of production for a full decade.

Basically, it's never going to feel like you're underpaying for Ohtani, at least not egregiously so. But you do run the risk of overpaying him both to a degree and length that could cripple the franchise through 2035—or longer if it's a deferred contract in which he gets something like $20 million annually for 26 years.