Red Sox relief pitcher Chris Martin has pitched 28 1/3 innings for this season. He has an ERA of 1.57 and 23 strikeouts. Chris Szagola/Associated Press

BOSTON — The Red Sox sent one lockdown reliever to Seattle for Tuesday’s All-Star Game with closer Kenley Jansen serving as the team’s only representative. If Jansen had his way, one of his bullpen mates would have joined him.

While Jansen received All-Star honors after a strong first half in which he went 19 for 21 in save opportunities and struck out 36 batters in 30 2/3 innings, setup man Chris Martin has been, by many metrics, even better. In 28 2/3 innings, the veteran owns a 1.57 ERA and 2.44 FIP while recording 23 strikeouts. Opponents have boasted a minuscule .542 OPS against him.

In terms of bWAR, Martin (1.6) has actually been the much more valuable reliever than Jansen (0.8) so far this season. The All-Star process, however, has always rewarded closers, who are usually bigger names, and this year was no different. Of the 11 relievers selected to represent their respective leagues in Seattle, only one – Baltimore’s Yennier Cano – has fewer than 14 saves. And Martin, who has just one save and missed the second half of April with shoulder inflammation, ranks 33rd among relievers in WAR, per FanGraphs.

Still, Martin has been tremendously valuable to the Red Sox, who made a commitment to improving their bullpen over the winter by handing out sizable deals to both Martin (two years, $17.5 million) and Jansen (two years, $32 million) in free agency. Jansen, who has aptly handled the ninth inning, has been more than impressed with how Martin has handled the eighth.

“Unbelievable, man. Unbelievable,” Jansen said Sunday. “I think we both feed off each other. (Him) knowing that I’m behind him and I know that he’s in front of me and he’s going to get the job done. He pushes me and I’m pushing him. That’s the feeling I have. Me and him, it’s a great 1-2 punch and hopefully he can stay healthy, I can stay healthy and we can be in this thing.”

Kenley Jansen was named the AL All-Star team after going 19 for 21 in saves opportunities for the Red Sox in the first half. John Bazemore/Associated Press

Jansen, 35, and Martin, 37, have never played together before this season despite coming close in years past. Martin pitched for the Braves from 2019 to 2021, only to leave for the Cubs in free agency before the 2022 season, when Jansen joined Atlanta. Jansen pitched for the Dodgers for the first 12 years of his career but had left by the time Los Angeles acquired Martin from the Cubs last summer. By the time Jansen signed with the Red Sox in December, Martin was already on board as the setup man.

The results have been stellar. The Red Sox have just seven blown saves this year – which is tied with San Francisco and Philadelphia for the fewest in baseball – after having 27 (tied for ninth-highest) in 2021.

Martin’s ability to bridge the gap, to Jansen, especially since returning from the injured list on May 1, has been a big reason why. In his last 23 appearances, Martin has allowed just three runs in 21 2/3 innings (1.25 ERA). He has struck out 21 batters and walked just two while throwing strikes at a 77% clip. Opposing hitters have posted a low average of .213.

“He’s just a strike-thrower with good stuff,” said Red Sox Manager Alex Cora. “He posts. He’s really good at what he does and he has been dominant. Early on, a little bit banged up. We did what we needed to do to get him reset. Since he came back, he has been great.”

Cora enjoyed the luxury of having future Hall of Famer Craig Kimbrel close for him in 2018 but was forced to get creative with bullpen structure in the years since. Between 2019 and 2021, 20 different pitchers closed games for the Red Sox, and despite temporary flashes from Brandon Workman and Matt Barnes, the club never had a lockdown option at the back end. Now, they have two.

“It’s two innings of really good stuff,” Cora said.

Cora expects the back end of his bullpen to get even better in the second half of the season. Reliable seventh-inning man John Schreiber, who posted a 2.12 ERA in 17 innings before getting hurt in mid-May, is expected back around July 20. A healthier rotation will allow Nick Pivetta to return to a one or two-inning role in close games and Josh Winckowski has largely proven capable as well. Between Brennan Bernardino, Chris Murphy, Brandon Walter, Joely Rodríguez and the injured Richard Bleier, the Sox should be able to find a couple lefties capable of getting big outs. A trade acquisition cannot be ruled out either.

“Schreiber was throwing the ball outstanding when he got banged up,” Cora said. “I’m looking forward to have the three of them with everybody else around them contributing and see where it takes us.”

Jansen, who has accomplished just about everything a reliever possibly could, has marveled at his setup man’s performance all season. He thinks Martin should be in Seattle with him, along with a couple other Red Sox teammates.

“He should have,” Jansen said. “A lot of people should have.”