The case for each pitcher in the race for a spot in the Red Sox starting rotation

The Boston Red Sox have been searching for another starting pitcher to round out their rotation all offseason.

The recent season-ending injury to Lucas Giolito has made the need even more pressing — the Red Sox now need two pitchers to complete a five-man rotation.

Boston began with four pitchers in the race for the fifth starting spot — Tanner Houck, Josh Winckowski, Garrett Whitlock and Cooper Criswell. Now, the fourth and fifth starting spots are up for grabs and, up until recently, the four hurlers were in a relatively close race for the positions.

But after his most recent spring training start went awry, Winckowski has been officially moved to the bullpen. The Phillies got to Winckowski early in the action on March 14, and the 25-year-old gave up five earned runs off eight hits in 3.2 innings.

Winckowski falling out of the race leaves three hurlers in the running for two spots. Here are the cases Houck, Criswell and Whitlock have made and where they could end up this season.

The case for each pitcher in the race for a spot in the Red Sox starting rotation

Tanner Houck

Houck has been a part of Boston's starting rotation before, so he knows the demands of the job. He's also shown the most progress of all the pitchers in the Red Sox's lineup from last year.

Houck's goal this offseason was to throw more strikes and he's been making good on his efforts. In his 15 Grapefruit League innings, Houck has fanned 16 batters and he's allowed just three walks, which is a huge improvement from his 2023 spring numbers. In his 20.1 innings pitched last spring, he struck out 25 batters, but he let up 20 free passes.

Houck is also being hit far less frequently than he was in 2023. Last spring, he let up 27 hits and 22 earned runs. This year, he's allowed just 10 hits and four earned runs. His 2023 numbers were based on 20.1 innings of work and he's only pitched 15 frames at the time of publication, but the point still stands — Houck's pitching has improved significantly since last year.

The righty logged a 5.01 ERA in his 21 regular season appearances in 2023 — he spent some time on the sidelines after being hit by a comebacker that fractured his face. Houck struggled with longevity as he let up 41 walks and 59 earned runs over his 106 innings. As an improved strike thrower, Houck's longevity issues should diminish. He should be able to throw fewer pitches and go deeper into games without allowing as many runs.

Houck's improvements have placed him firmly in first place for a rotation spot among Boston's starting options.

Garrett Whitlock

Whitlock was also on the Red Sox last year and his change in appearance was one of the highlights of Boston's winter — he packed on muscle that has garnered comparisons to Red Sox legend and new spring training helper Jon Lester.

Whitlock has had his ups and downs this spring, but his performances seem to be evening out for the better. His Friday outing against the Twins was his best yet. In 4.1 innings, Whitlock posted five strikeouts and one walk. He allowed two hits, but nothing came of them.

In 2023, Whitlock served as one of Alex Cora's flexible pitching options, moving between the rotation and the bullpen. His 2024 Grapefruit League numbers show improvement from last season's work — he logged a 5.15 ERA and 13 home runs allowed over 71.2 innings in 2023. It was far from Whitlock's best year, as he pitched nearly seven fewer innings than he did in 2022, but he allowed 17 more hits, 11 more runs and three more homers.

Whitlock himself wasn't proud of his 2023 showing. If the new-look pitcher can find his 2021 or 2022 form this season, he could very well earn Boston's final rotation spot. If he does not, he'll be a great addition to the Sox's bullpen instead.