ANAHEIM -- The Angels' medical staff and Dr. Steve Yoon were "very optimistic" about the prognosis of Shohei Ohtani's Grade 2 UCL sprain in the aftermath of the platelet-rich plasma and stem cell injections Ohtani received from Yoon last week, manager Mike Scioscia said Monday.
Ohtani has begun his rehabilitation regimen, which includes one-armed swings, running and general strength training. Ohtani was seen in the clubhouse Monday with no sleeve, brace or other form of protection on his right arm.
Scioscia didn't provide a specific timetable on Ohtani's recovery process, only that he would reevaluated in two to three weeks. Scioscia also didn't expand on whether he'd be willing to use Ohtani as a hitter if the elbow sprain prevented him from pitching, although he did say that Ohtani's "swing is not impacting his ligament at all."
Calhoun back from DL
Kole Calhoun returned from the disabled list for Monday night's game and was hitting ninth against the D-backs, his first since May 31 against the Tigers. He had been out since then with a right oblique strain. Calhoun had been hitting .145/.195/.179 with one homer and a wRC+ of 3 over 173 at-bats before the injury, so he took the trip to the disabled list in stride, using it as an opportunity to reevaluate his approach at the plate.
"With all the stuff that builds over time and trying to bang your head against the wall to figure out how to get things going, it was nice -- not nice, it's never nice to go on the DL -- but it gave me a chance to put things into perspective and just come back and try to help this team win," Calhoun said.

He hasn't made any comprehensive changes to his swing, he says, but he has made a few small adjustments in order to compensate for both his slow start and the flareup in his oblique.
In Calhoun's first at-bat on a rehab assignment with Triple-A Salt Lake last Wednesday, he hit a homer. Overall, he went 6-for-19 over 20 plate appearances, notching a double, triple and a home run.
"Getting to go down there and getting to see some pitches once he was healthy was important," Scioscia said.
"That gave me a chance to look at things and see where I wanted to go from there and work with a couple guys down in Arizona," Calhoun added.
In a corresponding move, the Angels optioned outfielder Jabari Blash to Salt Lake. Blash went 2-for-18 with three walks during this stint with the Angels.
Worth noting
• Kaleb Cowart will begin a rehab assignment with Triple-A Salt Lake tonight against the Colorado Springs Sky Sox. He has been out since June 8 after spraining his ankle on the steps of the team bus.
• Garrett Richards has begun to play catch in his injury rehab. He has been on the 10-day disabled list since June 14 with a left hamstring strain.
• Jim Johnson, too, has started to play catch, but he is still battling through the stiffness of the lumbar strain that has kept him on the 10-day disabled list since June 12.
• Zack Cozart has not begun baseball activities, but he has received extensive therapy on the left shoulder subluxation that has kept him out of the lineup since June 14.
• Nick Tropeano has not picked up a baseball since inflammation in his right shoulder forced him out of the rotation on June 12. He, too, is going through therapy, and remains on the disabled list.