fb-pixelBreaking down baseball’s free agent starting pitchers Skip to main content
Red Sox

Striking performances: Breaking down baseball’s free agent starting pitchers

Dennis Eckersley: Hiring Andrew Bailey was a 'good move'
The hall-of-famer talks Red Sox pitching, why Andrew Bailey is a good hire and why he doesn't expect to see star Shohei Ohtani calling Fenway Park home.

It might take a while to find out which starting pitcher(s) the Red Sox add this offseason. The market remains in a state of suspended animation, with the free agencies of two-way marvel Shohei Ohtani and 25-year-old Japanese ace Yoshinobu Yamamoto damming the industry.

Teams are still wooing and awaiting word of the landing spots for those players. Teams heavily involved on Ohtani may, if spurned, put mountains of money in front of Yamamoto. The many teams spurned by Yamamoto, in turn, will scramble after the rest of the available pitchers — whether Blake Snell, Jordan Montgomery, Shota Imanaga, or others.


Against that backdrop, and given that Yamamoto is expected to meet with top suitors in person after the Winter Meetings, the current gathering in Nashville may end without the Sox’ rotation looking any better defined. But, at the least, new chief baseball officer Craig Breslow has been clear about what traits he wants to target.

“Fundamentally, the goal of pitching is to prevent runs from being scored. And I think you can do that by generating swings and misses, limiting walks, and managing hard contact. And we have to just keep working backwards from that,” Breslow told reporters at the Winter Meetings.

And where does working backwards lead?

“Develop stuff that can generate swings and misses in the strike zone,” he said.

Assuming the Sox are prioritizing the ability to miss bats or limit hard contact on pitches in the zone, how would this year’s free agent class look? First, it’s worth looking at the highest swing-and-miss rates on pitches in the strike zone among free agent starters.

(Note: The group of 50 free agent starters used for this list does not include Yamamoto and Imanaga, both because their in-zone swing-and-miss rates are unavailable and because the league differences prevent an apples-to-apples comparison. Trevor Bauer, who pitched last year in the NPB, and Julio Urías, who is on indefinite administrative leave because of a second violation of MLB’s domestic violence policy, also are excluded.)


That top-10 list points mostly to players with upside. Snell is the only top starter who appears on the list, and while he’s dominant, the two-time Cy Young winner works less in the strike zone than any starter in baseball, with a paltry 40 percent in-zone rate.

Brandon Woodruff’s place atop the list suggests why teams will be lining up to sign him even though he recently underwent shoulder surgery. The inclusion of James Paxton points to why he should see a healthy market, and Lucas Giolito will represent a bounce-back candidate.

Sean Manaea, who shuttled between the rotation and bullpen with the Giants last season, is a particularly interesting name, given that he spent the year with new Red Sox pitching coach Andrew Bailey and that he had a 2.25 ERA and 18-to-2 strikeout-to-walk in his last four starts.

While those pitchers did a great job of missing bats when working in the strike zone, it’s worth considering those who were effective — with strikeouts or bad contact — when working in the zone. Using xwOBA (expected weighted on-base average, a statistic that accounts for not only strikeouts and walks but quality of contact) on pitches in the strike zone, here are the leaders among free agents:

This list more closely resembles the presumed top tier of free agent targets, with Lance Lynn’s .357 in-zone xwOBA — the product of giving up a lot of home runs — explaining why he was in line for just a one-year deal despite his ability to miss bats in the strike zone. Snell, Paxton, and Manaea stand out for their presence on both lists (as does Woodruff, though he’s in a separate category given that his availability in 2024 is unknown).


What to take from these lists? At a time when teams look more closely at the components of success and expected numbers than at bottom-line marks such as won-loss record or ERA, there likely will be long lines for less-heralded free agents such as Paxton and Manaea, among others. In terms of the biggest free agent names, Snell stands out for stuff that can beat hitters in the strike zone, albeit with considerable risk given the infrequency with which he does work in the zone.

As Breslow works his way through his first offseason running the Sox, it will be fascinating to keep score to see how closely his moves track with his articulated values in building a staff.

Alex Speier can be reached at alex.speier@globe.com. Follow him @alexspeier.