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Craig Breslow’s first major league free agent signing as Red Sox chief baseball officer came Dec. 13 when he inked righty Cooper Criswell to a one-year, $1 million contract.

The addition wasn’t a big free agent splash. The 27-year-old has pitched in just 12 major league games with 10 of those outings coming in 2023. But Breslow, a pitching guru, obviously saw intriguing potential that the Red Sox can tap into.

“I loved what they both (Breslow and pitching coach Andrew Bailey) had to say,” Criswell said at Red Sox Winter Weekend. “I really think they like my arsenal of the movement of the sinker and sweeper. And then focusing in on that cutter. And then the changeup has improved, too, the past two years. So I think just really focusing in on that cutter. Me and Bails (Bailey) have been doing a little throwing program Driveline-wise, trying to gain a little velo here and there. So if I could be able to do that, that would be awesome.”

Criswell has one minor league option remaining. And so he could begin the season in Triple-A Worcester’s starting rotation, providing big league starting depth. He’ll also compete for a role out of Boston’s bullpen.

“They want me to come to spring training prepared to be a starter,” Criswell said. “Just because it’s easier if they want to move me into a bulk role out of the bullpen or even a reliever. Obviously it’s easier to transition from a starter to a reliever rather than a reliever to a starter. So I’m going to be geared up, ready for spring training to go as a starter.”

Criswell’s sweeper has been his most effective pitch in his limited big league sample size. He threw 154 sweepers last year, holding opponents to a .211 batting average (8-for-38) and .166 expected batting average.

“I would consider a sweeper one of my best pitches, for sure,” Criswell said. “I feel comfortable throwing any of those, especially the three — sinker/slider/changeup — any pitch, any count. I’m getting the confidence in the cutter just as much as the other three pitches.”

He began throwing the cutter for the first time in-game last year.

“So just messing around with grips and stuff,” he said. “Bails has been awesome with that. Just helping me on grips. I actually threw a bullpen yesterday and really liked the results that we’ve been getting on the cutter.”

He also said he has seen some velocity gains with his cutter and sinker. He has focused on becoming more rotational in his upper-half. He said his sinker was around 89-90 mph last year.

“Which is essentially where I was at yesterday in my bullpen,” Criswell said. “So for me to be there right now, I’m feeling pretty good.”