KISSIMMEE, Fla. -- Astros infielder/outfielder Jonathan Villar was held out of Thursday's brief morning workout at Osceola County Stadium after suffering a mild right ankle sprain in an outfield collision Wednesday with teammate Robbie Grossman.
Grossman, who suffered a bruised left quad on the play, was able to work out with the team and could return to game action on Friday, though manager A.J. Hinch said he would likely keep Grossman out another day. Both players are trying to make the club in a reserves role.
"We expect both of them to be fine," Hinch said. "We'll have to assess Villar day to day, and I think Robbie will be back if we need him [Friday]. I'm not sure we'll play him. That's more of my decision than a health thing."
Meanwhile, relief pitcher Josh Fields is still a few days from throwing off a mound after leaving Monday's game against the Braves with a mild groin strain. Fields is playing catch off flat ground to keep his arm in shape, and he said Wednesday he was feeling better.
"I've dealt with some minor strains and little tweaks before," Fields said. "I feel like it's in that same category and I don't know any timeframe, but hopefully it won't be too long. Honestly, it's just day to day."
Left-handed starter Brett Oberholtzer will return to Grapefruit League action on Sunday after being sidelined for more than a week with a mild lat strain and an illness. He threw 46 pitches in a Minor League game on Wednesday without incident.
"My goal is stay healthy and throw strikes and have an idea out there," Oberholtzer said. "I accomplished that."
Finally, right-hander Brad Peacock, who's building up his pitch count following offseason hip surgery, threw in the bullpen on Thursday and will make his Grapefruit League debut on Sunday against the Yankees. He'll throw three or four innings.
"I'm feeling good and can't wait to see what I got when I get out there," Peacock said.
Peacock, who underwent arthroscopic surgery Oct. 6 to repair a torn labrum and remove bone spurs in his right hip, will likely start the season on the disabled list, but could be ready to pitch in games not long after. He started last season in the bullpen before making 24 starts, setting career highs in appearances (28), starts (24), innings pitched (131 2/3) and strikeouts (119). Peacock went 4-9 with a 4.72 ERA.