BOSTON -- Eduardo Núñez, who gave the Red Sox a big spark down the stretch in 2017 and belted a pinch-hit three-run homer in Game 1 of last year's World Series, was designated for assignment on Monday.

Nunez, a popular veteran, lost his spot on the roster due to his struggles against left-handed pitching this season.

"He's a smart baseball player. He helped most of the guys over there, especially Xander [Bogaerts] and Raffy [Devers]. That's part of the business," said Red Sox manager Alex Cora. "It's a tough one, because he's very likable, he meant a lot to the clubhouse and to the team, but that's part of this. You make tough decisions and you have to move on."

In 75 plate appearances against lefties this season, Nunez slashed .200/.240/.314 with two homers and 10 RBIs. He was only slightly better against righties.

To replace him on the roster, the Red Sox recalled first baseman Sam Travis from Triple-A Pawtucket. In the coming days, Boston also expects to get Mitch Moreland back from the injured list.

"It wasn't working out against lefties," said Cora. "Where we're at roster-wise, Michael [Chavis] is going to play against lefties and righties most of the time. I feel that we need more offense against left-handed pitching. It was a tough spot for him not getting enough at-bats. Actually, he was hitting better against righties.

"It's a tough decision, but it's a baseball decision. Sammy is swinging the bat well. He'll play most likely against lefties, first base, Michael will play second, and we'll go from there."

When a player's contract is designated for assignment -- often abbreviated "DFA" -- that player is immediately removed from his club's 40-man roster, and 25-man roster if he was on that as well. Within seven days of the transaction (it was previously 10 days), the player must either be traded, released or placed on irrevocable outright waivers.

After flourishing for the Red Sox following his acquisition from the Giants in 2017, Nunez was never the same player after suffering a serious right knee injury late that season.

The Red Sox and Nunez both felt the knee was a lot stronger heading into this season, but he couldn't recapture the results he had before the injury.

"He wasn't able to get in a rhythm. It's tough, because we get Michael and he starts swinging the bat well and playing time was limited," said Cora. "Brock [Holt] comes in and you see what he's doing. He's still a good player. [Nunez] did a good job for us last year. He was huge for us in the playoffs, that big swing against L.A. For everything that people say about his defense, whatever, he made some nice plays against the Yankees [in the American League Division Series]."

Nunez took the news like a professional and will now try to hook on somewhere else.

"Very professional," said Cora. "He knows. He's been around the game for a while. I don't know if he saw it coming or whatever, but he understands. It's always tough, obviously, but he's a guy that's been around the game for a while and knows that there's certain days that it sucks, and today's one of those days."

The Red Sox had some other roster moves in advance of their four-game series against the Blue Jays, which started Monday night. Righty Hector Velázquez was optioned to Pawtucket and righty Ryan Weber was recalled from Triple-A to take his spot on the roster.

Velazquez, 30, is 1-4 with a 5.67 ERA, 44 strikeouts and 21 walks through 24 appearances (eight starts) this season. He gave up three runs in the 12th inning Sunday on a pair of walks and two hits.

Only one of the runs was earned after Holt misplayed a grounder to first, forcing Velazquez to race to the bag, which resulted in Velazquez being called for interference on the basepaths.

Weber, 28, is 1-1 with a 5.12 ERA through six games (19 1/3 innings) in the big leagues this season. He owns a 2.35 ERA across his past four starts with Pawtucket.