Lester's second Triple-A rehab start -- on Wednesday night for the Pawtucket Red Sox in an International League game against the Indianapolis Indians -- was short-circuited because of a cramp in his left forearm.
Lester, who overcame a battle with anaplastic large cell lymphoma (a cancer that affects the lymphatic system), was removed by PawSox manager Ron Johnson after three innings. The 23-year-old was scheduled to throw approximately 90 pitches but wound up throwing only 63 (39 for strikes).
"The forearm tightened up a little bit in the third," Lester said. "Hopefully, it doesn't set me back. Hopefully, in five days I'll make another start and everything's fine. I don't know if [the cramp] was because of dehydration or what. But it was a little cramp in the forearm. I threw a pitch and it kind of tightened up. It was one of those freak things that happened.
"[Johnson] wanted to take me out. [He] didn't want to take any risks. Obviously, it's frustrating, but this is one of those things."
After Lester was removed from the game, he was examined by team physician Dr. Brian Busconi and trainer Greg Barajas.
"The doctor checked it out and said it was fine ... that it was just a cramp," Lester said. "I didn't have any tests, and I don't see any reason for them. It's in the forearm. There's nothing to be worried about in the elbow.
"Before that, I felt good. But like I said, in five days I'll make another start."
Where Lester will make that next start is a question yet to be answered. His 30-day rehab assignment ends on May 5, at which time Boston must decide whether to activate him or leave him in the Minors, ostensibly at Pawtucket, for additional work.
"I don't know anything," Lester said. "I'll find out one of these days what the deal is going to be, but obviously this doesn't help my situation."
"We can't do it ahead of time," Boston manager Terry Francona told MLB.com on Tuesday. "Our No. 1 responsibility is to Lester and his long-term health. You can kind of read into that what you want."
Lester's pitching line on Wednesday read virtually the opposite of what it did on April 27, against Buffalo, when he tossed five innings of three-hit scoreless ball, with zero walks and six strikeouts.
Against the Indians, Lester allowed two runs (both earned) on three hits and three walks, and fanned four. He topped out at 93 mph on the McCoy Stadium radar gun and consistently hit 91 and 92.
But the first inning was an indication that his command and control weren't as sharp as they were against Buffalo. He needed 25 pitches to navigate his way through the inning as Indianapolis scored twice on two hits (including a hit-and-run double by Jose Hernandez), plus a walk and a stolen base.
"I threw too many fastballs and didn't use my offspeed pitches enough early in the game, which is usually what I try to do," Lester said. "I left a cutter up and away to Hernandez [in the first], and he hit it down the line. But stuff-wise, I was all right. All in all, I felt good until the third inning."
Lester retired the side in order in the second on 12 pitches, including a strikeout of Luis Ordaz on a nasty changeup.
Indianapolis loaded the bases with two outs in the third on a hit, two walks and a fielder's choice. But Lester escaped without allowing a run by catching Hernandez looking at a third strike.
"I'm close," said Lester. "I'm around the zone. I hate to walk three guys. I said it was probably going to be one of those nights where it was going to be a grind."
Grind or not, Lester indicated that he is optimistic about the progress he's made during three rehab starts for Class A Greenville plus two for Pawtucket.
"I'd say I'm further ahead than I thought I would be," he said. "I didn't expect things would have gone this quickly, but they have, and I'm thankful for it. Hopefully, we can take another step in five days and see where we are then."
Where Lester was in the third inning was indicative of his mindset in that he felt there was a problem and wasn't inclined to take any chances.
"When he came off the mound in the third, he said he had a little cramping in his forearm," Johnson said. "Obviously, that was an easy decision for me. You're done. This is a rehab assignment, and we want to get him right so he's prepared to go to Boston."
Mike Scandura is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.