The Red Sox took plenty of heat this past offseason for failing to make a lot of big splashy moves, but a quarter of the way through the season many of the club’s under-the-radar additions have proven impactful.

Few more than right-hander Greg Weissert.

Acquired from the Yankees as part of this past winter’s Alex Verdugo trade, Weissert has quietly emerged as a vital part of the Red Sox bullpen. The 29-year-old currently leads the Red Sox in games pitched (17) and has posted a 1.56 ERA over his first 17.1 innings.

“It’s been awesome, I’ve finally gotten to be a part of the team and stay here for as long as I’ve been here,” Weissert said. “It’s been nice to get consistent work in the big leagues and settling in to the role.”

Though typically used in lower-leverage situations, Weissert has been dominant against righties and has given the bullpen the sort of depth it’s frequently lacked in recent years.

His advanced metrics also jump off the page: according to Statcast he ranks in the top 10% of baseball in expected ERA (2.11, 97th percentile) and barrel percentage (2.3%, 93rd percentile), and is among the top 25% in most other categories.

“He throws hard, he has a good changeup, good slider, he can get lefties and righties out,” Red Sox manager Alex Cora said. “I believe he can be better against lefties but his stuff is really good.”

“He’s a vital piece to what we’re trying to do here,” said pitching coach Andrew Bailey. “He’s got phenomenal stuff and some leadership traits that really help the bullpen.”

Before coming to Boston it often seemed like nothing Weissert did was enough for him to stick in the big leagues. Last year he bounced back and forth between New York and Triple-A Scranton/Wilkes-Barre a combined 10 times, and on three separate occasions he was called up to pitch one game, only to be sent back down immediately afterwards.

Now Weissert has already tied his career-high for big league appearances in a season, and Monday he delivered perhaps his most important outing of the season. His two innings helped reset the bullpen, putting the team in a better spot for the rest of the series, and his holding Tampa Bay to one run in the eighth after things nearly got out of hand gave the Red Sox a chance to win.

“As out of hand as it seemed after the first three batters in the second inning, it’s important to take it pitch by pitch and just make sure you’re making quality pitches at that point, because it’s easy to give in at that point when it’s already not going your way,” Weissert said. “It’s a learned skill almost where you need to be able to lock back in and think about it objectively. I need to make one pitch at a time, I don’t need all three outs to happen in this moment, but if I can calm down and just make one pitch at a time, it’s giving you a way better chance to get the job done.”

Weissert threw a career-high 43 pitches to make it through his outing, and in past years that almost certainly would have led to his being optioned to Triple-A for a fresh arm. Now Weissert is enjoying his newfound stability and hopes to ensure his current stay in the majors will be a long one.

Small additions adding up

Weissert isn’t the only newcomer who has carried his weight in the bullpen. Rookie Justin Slaten (1.74 ERA) has also established himself as a crucial relief option since being acquired from the Mets following the Rule 5 Draft, and Zack Kelly (2.16 ERA) has settled in after getting his first extended big league run. Cooper Criswell (2.10 ERA) has effectively kept the starting rotation afloat through its recent run of injuries, and Isaiah Campbell is expected to play an important role upon his return from the IL.

“We’re in a good spot,” Cora said. “We’ve got some good arms in Triple-A. (Josh Winckowski) is in Triple-A, and he’s a good pitcher. As far as the talent and how deep we are, we’re in a much better spot than the last few years.”

Richard Fitts, who was acquired alongside Weissert in the Verdugo trade, is likely to make his mark in the majors sooner rather than later. Fitts is 3-1 with a 3.51 ERA over 33.1 innings at Triple-A and is currently ranked Boston’s No. 10 prospect according to MLB Pipeline.

Nicholas Judice, the third pitcher acquired in the Verdugo trade, is currently on a throwing progression after being slowed down in spring training for non-baseball reasons, according to a Red Sox source. The 6-foot-8 right-hander is expected to continue ramping up before appearing in any minor league games.

Extra innings

Garrett Whitlock is scheduled to throw three innings during his rehab start in Worcester on Wednesday morning. Cora said he was up to 94-95 mph in his recent live batting practice session. … Isaiah Campbell (right shoulder impingement) will throw a live bullpen on Thursday. … Mikey Romero, the Red Sox first-round pick in 2022, has been activated from the minor league injured list and assigned to High-A Greenville. The 20-year-old shortstop should soon make his debut after missing most of his first full professional season with a back injury.