John Farrell neither crossed his fingers nor held his breath. But as the Red Sox left for a flight home last night, the manager was anxiously awaiting results of right-hander John Lackey’s MRI exam.

Indications, however, were that Lackey felt better than on Saturday, when he left his start in the fifth inning after grabbing his right arm. And although the Sox won’t exhale until consulting with team doctors today, they were cautiously optimistic that Lackey avoided serious injury.

“I think we’ll know more after the information is returned from the MRI,” Farrell said. “First and foremost is John’s well-being. Given all that he has come through, or just given that a pitcher walked off the mound in the midst of an at-bat, we’ve got to be cautious with this.”

Lackey was diagnosed Saturday with a “right biceps strain,” but he returned to Boston yesterday for an appointment at Massachusetts General Hospital with Dr. Peter Asnis, the team’s head orthopedist. Lackey underwent a full exam, including an MRI, to confirm the initial findings by the athletic trainers.

Making his first start in 18 months after returning from Tommy John elbow surgery, Lackey reported a cramping sensation in his biceps in the fifth inning Saturday. But the symptoms had subsided shortly after he left the game, and he wasn’t experiencing the numbness or tingling that accompanied the damaged elbow ligament that required surgery in October 2011.

Assuming Lackey needs to miss at least one start, Farrell said the Red Sox haven’t decided how to fill his spot in the rotation. With a day off tomorrow, it’s possible they won’t need a No. 5 starter until Sunday’s game at Fenway Park against the Tampa Bay Rays.

Drew on deck

If not for a rare “freeze-out” at Double-A Portland, shortstop Stephen Drew may be making his Red Sox debut today at Fenway Park.