Right-hander Matt Barnes, a 2021 All-Star and a career Red Sox pitcher, will be moving on from Boston.

The Red Sox designated the reliever for assignment on Tuesday to make room on the 40-man roster for free agent acquisition Adam Duvall, a versatile defensive outfielder who also hits for power.

Also on Tuesday, Boston strengthened its middle-infield depth by trading with the Kansas City Royals for Adalberto Mondesi.

Barnes, 32, was 0-4 in 2022 with eight saves and a 4.31 ERA in 39 2/3 innings over 44 games. He allowed 36 hits, 22 runs (19 earned) and 21 walks with 34 strikeouts.

Only briefly the longest-tenured Red Sox player after infielder Xander Bogaerts signed as a free agent with the San Diego Padres in December, Barnes began with the organization as a first-round draft pick (19th overall) in 2011 out of the University of Connecticut.

He made his major league debut in 2014 at age 24 and made the American League All-Star team in 2021 when he recorded a 3.79 ERA, 24 saves and a 6-5 record in 54.2 innings over 60 games. Barnes was a key contributor to Boston's 2018 World Series championship team.

Due $7.5 million for the 2023 season plus a $2.25 million buyout for 2024, Barnes was taken off the 40-man roster. The ballclub has seven days to trade him or place him on put him on irrevocable waivers.

"Obviously a really, really difficult decision," Red Sox chief baseball officer Chaim Bloom said. "The conversation itself (with Barnes) was one of the more difficult ones that I've had. Obviously the DFA process needs to play out, so there's a limited amount that I want to say about it until it does.

"But, you know, I think more than anything, this is just a function of where we're at in the offseason and with our 40-man roster. There are no easy decisions and regardless of recent accomplishments, regardless of what they have under their belts in their careers, everybody on our 40-man roster has real value.

"And so that forces tough choices, and it's obviously something we've been working through all offseason. And today we landed on Matt, but beyond that, it's certainly nothing negative about him."