Amidst their longest losing streak since September 2022, the Red Sox made three bullpen-related roster moves Saturday afternoon.

Rookie right-hander Luis Guerrero has been placed on the 15-day injured list with an elbow sprain. There are no plans to send him for an MRI at this time, manager Alex Cora said.

Between his debut last Sept. 8 and April of this year, Guerrero began his big-league career with 12 consecutive scoreless appearances, the most by an American League pitcher since Austin Maddox’s Red Sox debut in 2017. In franchise history, the only longer streak of its kind belongs to Robby Scott (2016-17).

Since the beginning of June, however, Guerrero owns a 5.25 ERA over nine games, with 11 walks and just six strikeouts in 12 innings.

Left-hander Chris Murphy was reinstated from the injured list. He missed the entire ’24 season due to Tommy John surgery last April 10. He last pitched for Boston in September ’23, after making his major league debut on June 7 of that year. Over 20 career appearances for the Red Sox, he owns a 4.91 ERA, but a 3.70 FIP.

“We’re pleased with the progress and where he’s at physically,” Cora said of Murphy. “It was the right move. (Brennan Bernardino) went on longer than expected yesterday, Luis going on the IL, so it made sense to add the lefty here.”

The Red Sox also transferred right-hander Justin Slaten (shoulder inflammation) to the 60-day injured list, but Cora assured it was a formality. Slaten will be eligible to come off the IL at the end of July, and his progression will take at least that long. He began baseball activities this week, but the Red Sox don’t want to rush the righty.

“It was slower than expected. He wasn’t feeling great,” Cora said, noting that Slaten’s shoulder felt “weak” during every test. “Timing-wise, it’s gonna take that … like I was telling (chief baseball officer Craig Breslow) yesterday, I said, ‘This guy’s very important for us, so we cannot rush him.’ “

Slaten was one of Boston’s most reliable relievers in his ’24 debut season, posting a 2.93 ERA over 44 appearances (55.1 innings). Through 24 games this year, he owns a 3.47 ERA but has struggled at times to put batters away. His strikeout percentage down significantly — 17.8% compared to 25.9% last season — and he’s walked batters at a 7.8% clip, nearly double his ’24 rate of 4.0%.

Jordan Hicks, one of the players acquired in the Rafael Devers trade, made another rehab appearance (right toe inflammation) for Triple-A on Friday night. The 28-year-old righty pitched a scoreless fifth inning with one hit, a walk and a pair of swinging strikeouts. The hard-thrower’s four-seam topped out at 99.7, but his hardest pitch of the outing was a 100.1 mph sinker. Hicks could be activated as early as Monday.

The Red Sox entered Saturday 40-43, in large part due to their MLB-worst 17 blown saves.

“You add him to (Aroldis) Chapman, (Justin) Wilson, (Garrett) Whitlock, (Greg) Weissert, it’s a good unit back there,” said Cora of Hicks. “Hopefully when Slaten’s back, everybody’s healthy and we can have a dominant bullpen.”

Cora’s All-Star picks

Beyond Garrett Crochet and Chapman, which Red Sox deserve to be All-Stars this year?

“I think numbers-wise, I think Alex (Bregman) is still up there as far as (Wins Above Replacement) at third base,” said Cora on Saturday. “Carlos (Narváez), as far as WAR, is up there, too.”

Boston’s 2.0 WAR at third base is the best mark in the American League by far; no other team’s hot corner is worth more than 1.6 (Cleveland). Bregman is worth 2.9 WAR, just shy of the top-10 among all AL position players. He’s a top-10 AL hitter in Adjusted Batting Runs and Adjusted Batting Wins. And despite not playing since May 23, Bregman entered Saturday leading AL third basemen in double plays turned, third in Total Zone Runs, and fifth in assists.

Narváez leads AL catchers in assists (35) and runners caught stealing (17). He’s played to 1.5 offensive WAR and his 1.3 defensive WAR is the sixth-best mark among all AL position players.

The Red Sox had three All-Stars last season in Rafael Devers, Jarren Duran — who was named the game’s MVP — and Tanner Houck.

Bregman is Boston’s only finalist to be an All-Star starter, but he likely won’t be able to play as he continues to rehab his quad strain. Narváez could be named a Team AL reserve.

“That’s about it, right, where we’re at,” Cora said.

The 2025 MLB All-Star Game will take place Tuesday, July 15 at Atlanta’s Truist Park.

Extra innings

The Red Sox hope to send Masataka Yoshida on a rehab assignment with Triple-A on Tuesday. … Bregman ran and took grounders at Fenway on Saturday afternoon. … The Red Sox haven’t had good weather on a single Saturday this season. They were in San Francisco last weekend when the sun finally came out after 13 consecutive rainy Saturdays, a new Boston record.