Why Red Sox traded him — and who might replace him in bullpen

FORT MYERS, Fla. — The first notable roster move of Red Sox spring training came in the way of subtraction, not addition, as reliever John Schreiber was traded to the Royals for pitching prospect David Sandlin on Saturday. The deal takes a piece away from the major league roster to add farm depth, by definition lessening Boston’s playoff chances in 2024. But according to chief baseball officer Craig Breslow, it’s one the Red Sox felt like they had to make.

Boston entered camp with a surplus of right-handed major league bullpen options after adding a handful of them over the offseason. Conversely, the organization lacks starting pitching prospects as a whole. Breslow saw a chance to achieve some balance even if his big league roster got worse.

“We’ve talked for a while about our right-handed relief depth,” Breslow said. “It’s something we feel strongly about and confident in. And the need, when the opportunity exists, to create more starting pitching depth. I think this was one example of a chance to do this.”

It’s no secret that the Red Sox have considered dealing from their relief group throughout the winter but the fact they moved Schreiber, and not a more expensive veteran like Kenley Jansen (owed $16 million) or Chris Martin ($8.75 million), comes as a bit of a surprise. Perhaps Breslow thought he could get more of a return for Schreiber, who is due $1.175 million and is under control for three more seasons, than an older player like Jansen or Martin, who are both in their final years under contract.

Another factor making Schreiber expendable is the number of high-upside righties the Sox have amassed on their 40-man roster. With Jansen and Martin projected to anchor the back end, there will be a stiff competition for the remaining spots. Tanner Houck, Garrett Whitlock and Josh Winckowski are all competing for the fifth rotation spot but two of three of them will likely end up in the bullpen. Isaiah Campbell, Cooper Criswell, Zack Kelly and Greg Weissert all have minor league options remaining and big league experience. Rule 5 pickup Justin Slaten and out-of-options former top prospect Bryan Mata are also in the mix and have to make the Opening Day roster or risk being exposed to waivers.

Slaten and Mata will get a long look because of their unique situations. But the competition is an open one. Assuming everyone’s healthy, there may be three open spots for a mix of the aforementioned righties and potentially, a lefty like Lucas Luetge, Chris Murphy, Joe Jacques, Brandon Walter or Jorge Benítez.

“It opens the window for other guys to step up and try to win that spot,” Cora said. “We traded from an area that we feel we’ve got other cards that can help us this year. Obviously, we added some upside at the minor league level.”

“I think there are a number of guys,” Breslow said. “We’ve made some acquisitions this offseason, whether that was Campbell or Weissert. Some guys who spent time in the ‘pen are getting built out as starters and we’ll have to see how that plays out. We feel really good about the back end. Depending on how the rotation competition plays out, plus the additions that we’ve made, it’s a spot we feel good about.

Cora, like Breslow, identified both Campbell and Weissert as early standouts in camp. Both right-handers were acquired over the winter, with Campbell being obtained from Seattle for infielder Luis Urías in November and Weissert coming over in the Alex Verdugo trade with the Yankees weeks later.