Jon Lester, shown on May 2 during his second rehab start for the Pawtucket Red Sox, has made it back to the big time, and will face the Indians tonight.

The Providence Journal / Ruben W. Perez

BOSTON — The road back has been long and filled with emotional ups and downs as well as physical challenges.

But Jon Lester has made it back to the big leagues.

The left-hander, who has battled back from non-Hodgkins lymphoma, which was diagnosed last August, will be on the mound tonight, starting for the Boston Red Sox in the opener of a four-game series in Cleveland.

Boston manager Terry Francona announced yesterday morning that Lester would be promoted and will take Julian Tavarez’s spot in the rotation. Tavarez, who has struggled recently, has been sent to the bullpen, and Joel Pineiro is being designated for assignment to make room for Lester. Tavarez was 0-2 with a 10.80 earned-run average in his last three starts.

“I think this (call-up) is more gratifying than last year, just for the simple fact of the road I’ve been coming back from last year,” said Lester, who was 7-2 with a 4.76 ERA. in 15 starts for Boston last year before being sidelined for his cancer treatments.

“I don’t think it really has sunk in yet and I don’t think it will sink in until (tonight) when I get on the mound,” said Lester from Pawtucket, where he had a workout.

Lester, the Sox’ second-round draft pick in 2002, was 5-8 with a 3.89 earned-run average in 14 starts for the PawSox this year.

The Red Sox have been very careful with their handling of Lester, 23, wanting to make sure he was healthy enough and strong enough to handle the rigors of pitching in the big leagues before calling him up.

After having gone through cancer treatments, Lester was able to arrive at spring training on time, but it wasn’t until recently that the Sox decided he was ready to return to the majors, especially with Tavarez’s recent struggles opening the door in the rotation.

“I don’t know if it was myself or John (Farrell, the Sox’ pitching coach), but we asked RJ (Pawtucket manager Ron Johnson), ‘If we’re 100 percent and don’t need Lester, should Lester be here?’ And RJ said, ‘Yes.’ That clinched it for us,” said Francona.

“He’s been pitching better of late,” said general manager Theo Epstein. “His cutter has been better. We just think it’s good timing. It just made sense (to do it now). We’ll see if he’s ready to be back for good.”

The Sox have been weighing the interests of Lester as well as the interests of the ballclub. And Francona appreciates the fact that it has been tough for Lester to be in Pawtucket when the big leagues, which is where Lester proved to himself that he belonged last year, was only a few miles up the road on Route 95.

“He had to fight wanting to be here and pitching down there. He felt a commitment to come up here and help us win and (he was) pitching for Pawtucket. He had some frustrations. But he’s not your typical 23-year-old,” said Francona, referring to his maturity.

“Jon just wants to win the game. He’s ready to pitch. He just said, ‘OK, tell me where to be and when to be there.’ He was very businesslike,” said Francona.

Lester, who was inconsistent at times in Pawtucket, admitted the toughest part of this season for him as been “just waiting” to get back to Boston.

“It was hard and frustrating to do the steps and the progressions (the organization) had, but as long as I sat back and kept telling myself that they want me to be healthy and that’s the main goal for the future, not now, (it was easier to handle),” said Lester.

“You have to sit back and see they have your best interests involved. They want you to be healthy. It’s been hard getting treated like you’re in a glass bottle, so it’s nice to finally break through it and get to go pitch again,” said Lester, who also missed some time this year because of a strained left forearm.

Lester says he will approach tonight’s assignment as “just a normal start, just like any other normal deal,” adding he expects he’ll be a bit nervous in the first inning.

But there likely will be quite a bit of emotion flowing at Jacobs Field.

skrasner@projo.com