BALTIMORE -- Brock Holt, on the concussion disabled list for the second time in the last three seasons, took his first round of batting practice on the field Wednesday afternoon.
"He's progressing,'' said John Farrell. "What we've come to know with these situations is that (when) you increase the activity, you increase the exertion just to get him re-conditioned and how his system gets re-calibrated and the balance in the brain, the equilibrium . . . that's the process he's in right now.''
Holt took fly balls Tuesday and again Wednesday. He's already taken some ground balls as part of his workout regimen.
"But we don't have a timetable for getting him out to get some live at-bats,'' Farrell said, "or even a return date, for that matter.''
It's assumed that Holt will eventually need to go out on a rehab assignment, though that shouldn't be for a prolonged period.
"With this,'' said Farrell, "you're talking about one of most difficult things in sports to do and that's hit a baseball. And he's going to need to see some live pitching. How many at-bats? That's still to be determined.''
Holt suffered a mild concussion last month when the Oakland A's were in town and he went in to play second base late in a game. He dived for a ball and felt a whiplash-like effect in his neck.
The neck was treated, but as those symptoms went away, he began to again experience some concussion-like symptoms. He also experienced a concussion in the final month of 2014 and missed the remainder of the season.
In Holt's absence, the Red Sox have been relying on Blake Swihart in left. While Swihart hasn't produced much offensively of late -- he's 4-for-15 on the current road trip -- he has adapted nicely to left.
"We didn't know how long it would take for him to feel comfortable,'' said Farrell. "We felt like his athleticism would allow him to (make the switch from catcher). It's been work on his part, but to his credit, he's transitioned fairly seamlessly.
"Even behind the plate, we felt he had good baseball instincts. We felt his overall athleticism was going to allow him to be adequate there. And what he's shown is that he's more than adequate.''