LOS ANGELES -- Phillies superstar Bryce Harper has been diagnosed with a small tear in his right ulnar collateral ligament and will be unable to throw for four weeks, according to manager Joe Girardi.

Harper will have a platelet-rich plasma (PRP) injection Sunday, which will take him out of the lineup for the series finale in Los Angeles and potentially on Tuesday at home against San Diego. But he was in the lineup for Thursday's series opener and homered in the first inning of Philadelphia's 9-7 victory.

“I’m glad that I know and have some clarity on where it’s going to go from here,” Harper said. “That’s about it. I’ll get the shot on Sunday, see how I feel the next couple of weeks and go from there.”

Fortunately for the Phillies, a universal designated hitter exists and Harper will, for now, remain a fixture in Girardi’s batting order. The injury, initially diagnosed as a strain, has restricted him to DH duty since April 17.

During that time, the reigning National League MVP has posted a .923 OPS with five homers and 12 RBIs.

“I miss playing [defense],” Harper said. “I really do. I miss being out there with my team and playing on the field. It’s been tough. I want to get back out there. I want to help this team on both sides of the ball. I miss playing right [field]. … That’s been a grind for me. Just worrying about hitting all day, instead of going out there and playing both sides of the ball.”

The tear was confirmed Thursday morning by Dr. Neal ElAttrache.

“It’s a new, small tear,” Girardi said. “Hopefully, the PRPs are soon over and he’s good to go.”

Girardi said he hopes Harper will begin a throwing program once the four-week period is through.