BOSTON -- Boston Red Sox ace Jon Lester suffered a lower lat muscle strain after four no-hit innings against the Toronto Blue Jays Tuesday night at Fenway Park and will be re-evaluated Wednesday morning.

After Boston's 3-2 victory over the Blue Jays, Red Sox manager Terry Francona said Lester would be examined "extensively" on Wednesday.

Depending on the severity of the injury, typically a lat strain could sideline a pitcher for 2-4 weeks, according to a team source.

"It was sore. It hurt," Lester said. "I would never take myself out of the game if it wasn't for something significant. We'll get it looked at tomorrow and see how I feel. Hopefully we've got the All-Star break worked in and hopefully we don't have to do anything drastic around here."

He said he has never had a lat issue in the past, but Francona said Lester has had experience with cramping during hot and humid conditions. Either way, Lester did not seem to be worried.

"I don't imagine this being a long-term deal," he said. "We'll re-evaluate everything tomorrow, but hopefully it was more of a precautionary-type deal, just a fluke thing and we'll move on."

"It's going to be sore tomorrow and it's going to be sore the next day," Lester said. "We just have to take action of getting it better every day. It's not something I'm worried about long term. It should be fine for the rest of the season."

Lester, who is 10-4 with a 3.31 ERA this season, explained that he didn't suffer the injury on one particular pitch. He felt the discomfort during the entire fourth inning.

"It just built up," he said.

Between innings, Lester was talking with team trainer Mike Reinold and the pair was trying to figure out a way for the southpaw to return to the mound in the fifth inning, but it didn't take long before the decision was made to end the outing.

"Him and Tito always have our best interest (in mind), so there's no point of going out there and pushing it right now," Lester said. "It's going to be sore tomorrow, but I think if I would have gone out there in the fifth I could have possibly done some worse damage."

"It felt like it was cramping on him and there's no way we were going to let him pitch," Francona said. "It was pretty obvious he felt good on the mound with the way he was throwing the ball. We'll get him checked out tomorrow and get more information."