HOUSTON -- Shohei Ohtani experienced yet another health scare in his long-awaited pitching comeback on Sunday night, but the Angels believe the issue is unrelated to the sprained elbow ligament that kept him off the mound for nearly three months.

Ohtani opened his outing against the Astros with two scoreless innings, but he showed a notable dip in velocity in the third, with his fastball dropping from 96-97 mph to 91-92. He subsequently surrendered a two-run home run to George Springer and departed after throwing 49 pitches over 2 1/3 innings in the Angels' 4-2 loss at Minute Maid Park.

Manager Mike Scioscia said Ohtani developed some back stiffness between the first and second innings and was also dealing with a sore right finger after attempting to make a barehanded snag on a comebacker in the second, precipitating the dip in velocity.

"The first two innings were electric," Scioscia said. "That's what you would expect. Third inning, obviously, his stuff wasn't as crisp. In talking to our medical staff, Bernard [Li] and Adam [Nevala], his back was a little tight. And when he took the ball off his ring finger, it just started to get a little bit sore. There was definitely a drop in velocity, but not connected at all to the thing that he had with his elbow before."

Scioscia said the Angels are hopeful Ohtani will be able to make his next start on the mound, which would be next Sunday against the White Sox if the club keeps him on his once-a-week schedule as expected. Ohtani also said his right elbow feels fine, though he added that he would wait to see how his body feels on Monday before saying anything definitive about his availability moving forward.

"I can't really say much at this point," Ohtani said through interpreter Ippei Mizuhara. "I've got to see how my body reacts."

Ohtani hadn't pitched in the Majors since June 6 because of a Grade 2 sprain of the ulnar collateral ligament in his right elbow. While the diagnosis sparked fears that Ohtani would require Tommy John surgery, general manager Billy Eppler has said that no doctor has recommended the procedure.

The ligament was treated with platelet-rich plasma and stem-cell injections on June 7 and Ohtani was cleared to resume throwing six weeks later. He has continued to serve as designated hitter and took the final step in his pitching rehab after completing a 50-pitch simulated game at Angel Stadium last Monday. Ohtani was held to a similar pitch count Sunday, though the Angels were prepared to deal with a short start after stocking their bullpen with relievers during the first round of September callups.

In the first inning, Ohtani gave up a leadoff single to Springer before retiring Jose Altuve on a flyout and Alex Bregman on a popout. He then walked Carlos Correa to put runners on first and second, but extricated himself from the jam by striking out Tyler White looking on a slider. His fastball topped out at 99.3 mph.

Ohtani breezed through a 1-2-3 second, though he hurt his finger after taking Marwin Gonzalez 's comebacker off his bare right hand. Ohtani returned to the mound for the third, but he immediately showed diminished velocity. His first three fastballs to Tony Kemp were clocked at 88.9, 90.2 and 91.9 mph as he issued a leadoff walk.

"When the ball made contact with my fingers, at first I didn't really feel any pain or anything," said Ohtani, who waved off Scioscia and the training staff after the grounder. "I just kept on throwing. But as the inning went on and it got to the third inning, I started to feel [discomfort] in the finger area. Maybe that had to do with something with the dip in velocity."

After walking Kemp, Ohtani misplaced a slider to Springer, who hit it out to left field for a 2-0 Astros lead. Ohtani coaxed a groundout from Altuve before giving way to reliever Jim Johnson.

"It was kind of hard getting through it with the low velocity, but I was trying to fight through it," Ohtani said. "I was trying to get out of that inning within that pitch count, but obviously I gave up that two-run homer, so I was disappointed."

Despite the rough reentry on the mound, Ohtani accomplished a rare feat in baseball history. He has now logged a 3.31 ERA over 51 2/3 innings in 10 starts, joining Babe Ruth as the only players in MLB history to record 50 innings pitched and hit 15 home runs in a single season.

In addition to his work on the mound, Ohtani is also batting .276 with an .897 OPS and 15 home runs in 80 games as a left-handed hitter.