The Red Sox are out to a decent start in 2024. Despite dropping five of their last six, they’re above .500 at 19-18. They’re currently in third place in a division where most observers felt they’d finish fourth or fifth. That’s a credit to a pitching staff that leads the majors with a 2.75 earned run average.

Boston’s bullpen looked solid coming into the year, yet the rotation was more of a question mark. It wasn’t that the group was devoid of talent. It was light on pitchers with a proven track record as starters, though, particularly after Lucas Giolito went down for the season in Spring Training. That left the Sox relying on a handful of pitchers who’d been productive as relievers to shoulder important rotation jobs. They’ve delivered thus far, with Tanner Houck and Kutter Crawford out to particularly excellent starts.

Houck and Crawford are the only members of Boston’s season-opening rotation who haven’t spent time on the injured list. Garrett Whitlock, Brayan Bello and Nick Pivetta have all missed time. (Pivetta returned on Wednesday and Bello could be back by the weekend.) Houck wasn’t even a lock for the Opening Day starting five until Giolito’s injury. By all accounts, the Sox rotation should have struggled to this point.

Instead, they easily lead the majors with a 2.33 ERA. That’s at least partially a reflection of their usage. Only the White Sox — whose rotation has been one of the league’s worst — have allowed their starters to face an opposing hitter for a third time in an outing less often. Alex Cora is getting to the bullpen early, which takes some of the higher-pressure at-bats off the rotation. Yet that doesn’t entirely detract from how effective Boston’s starters have been.

Crawford, 28, has appeared in parts of four seasons. He held a rotation spot from June onward last year, turning in solid if unexciting results. Over 23 starts, he worked to a 4.51 ERA with an above-average 26.2% strikeout rate. It was enough for the Sox to guarantee him a rotation spot even when they expected Giolito would be healthy. He went into 2024 with a season-opening starting job for the first time in his career.

The right-hander has doubled down on last year’s success. Through eight starts, he carries a 1.75 ERA that ranks seventh among qualified starters. He has fanned 24.3% of opponents and is generating swinging strikes at a solid 12.3% clip. Crawford has held opponents to two or fewer runs in seven of his appearances.

Crawford probably isn’t an ace. He’s not missing bats at the level associated with the game’s truly elite pitchers. He’s a fly-ball pitcher who’ll surely allow a few more home runs over the course of the year. Crawford looks like a legitimate mid-rotation arm, though. He’s attacking hitters with more offspeed stuff — part of a team-wide philosophical shift under new pitching coach Andrew Bailey — and has done an excellent job staying off barrels. That’s true against left-handed and righty batters alike, making it difficult for opponents to play matchups and allowing him to at least work through the batting order twice in a start.

That has also been true for Houck, at least this season. Concerns about the right-hander’s low arm angle and heavy reliance on a sinker/slider combination have led some evaluators to project him to the bullpen going back to his college days in Missouri. It’s difficult to avoid huge platoon splits with that kind of profile. Left-handed batters can identify the ball early in his delivery. For most of his career, Houck hasn’t had a pitch to keep opposing southpaws at bay.

Houck kicked between starting and relief over his first three-plus seasons. He worked out of the rotation for all 21 of his appearances last year but struggled to a 5.01 ERA. Handling left-handed hitters was indeed an issue. Through the end of the 2023 season, Houck stifled righties to a .214/.282/.283 batting line behind a 27.4% strikeout rate. Lefty batters turned in a much more productive .251/.343/.420 slash while striking out 22% of the time. Lefties drew more walks and hit for much more power against him.

That hasn’t been the case this season. While Houck has still been better against right-handed hitters in 2024, that’s more a reflection of his dominance against everyone than any kind of issue handling southpaws. Houck is holding left-handers to a .227/.279/.258 slash in 104 plate appearances. His 21.2% strikeout rate isn’t great, but he has more than halved his walks and pushed his ground-ball percentage north of 60%. Even if they’re still putting the ball in play at a decent clip, lefty batters aren’t doing any kind of damage. (Houck has completely befuddled right-handed opponents, limiting them to a .203/.234/.284 mark behind a huge 31.2% strikeout rate.)

As is the case with Crawford, Houck has found that new level by moving away from his heater. Houck has essentially doubled the usage of his splitter against left-handed batters while scaling back on his fastball and cutter. The split isn’t a new pitch — he has had it throughout his career — but he’s getting more downward action on it. The uptick in its deployment suggests Houck is far more comfortable with the pitch than he’d been before this year.

Whether Crawford and Houck can maintain an upper mid-rotation pace or better over a full schedule remains to be seen. Neither pitcher has yet reached 130 major league innings in a season. Opposing lineups will adjust to their heavier reliance on offspeed stuff, and league-wide offense generally improves as the weather warms. They’ve each been among the best pitchers in the majors through six weeks, though. These kinds of breakouts are necessary for a team to outperform expectations and stick in the playoff mix against the odds.

Images courtesy of USA Today Sports.