St. Petersburg, Fla. — Boston Red Sox second baseman Dustin Pedroia said he got good news about the irritation in his left knee that caused his return to the 10-day injured list.

The 35-year-old started the season on the injured list with inflammation in his left knee and was activated April 9. He left Wednesday night's game against the New York Yankees in the second inning and was examined Thursday, when Boston put him back on the IL.

"More kind of scared me than anything," Pedroia said before Friday night's game at Tampa Bay. "I was nervous, obviously, to feel that. We're just going to let it calm down for a few days and then it should be alright. I hadn't had any issues up until this point."

Pedroia felt a pop when he went to rotate on a swing.

"Sometimes the batter's box are a little tacky and things like that," Pedroia said. "The brace I wear is strapped around, so it kind of like torqued and my knee didn't."

Red Sox manager Alex Cora originally thought the injury could be serious.

"The way he reacted that day I was like 'oh, this is it right here,'" Cora said. "I was thinking the worst. I'm relieved. We got some positive news. Now it's just a matter to see how he reacts during the week. When he's ready, he's ready."

Pedroia will use a different type of brace when he returns.

Pedroia has appeared in six games with Boston, making four starts at second base and two as a designated hitter. He is 2 for 20 with a walk, one RBI and one run scored. He did not need an MRI.

"I've been through a lot," Pedroia said. "It's fun being out there playing. It was just a weird, freak thing."

Boston placed infielder Eduardo Núñez on the 10-day injured list with a mid-back strain and said right-handed pitcher Erasmo Ramírez was designated for assignment.

"It's been going on for a few days," Cora said of Nunez's back issues. "He's been fighting it. It gets to the point that, let's stay away from him, get him better."

Infielders Tzu-Wei Lin and Michael Chavis were recalled from Triple-A Pawtucket.

Cora said Lin will likely get the majority of the time at second base.

Chavis is on an active major league roster for the first time. The 23-year old was the 26th overall pick in the 2014 amateur draft.

"We'll find a way to get Michael at-bats," Cora said. "I'm happy for the kid that he's a big leaguer. Hopefully he can make an impact."