In the top of the eighth inning of Game 4 of the NLDS, Philadelphia Phillies star Bryce Harper left the field with visible pain to his right arm, appearing to grab the elbow area after Matt Olson made contact with it.

Harper, who is playing first base for the first time this season, was reaching out to secure the out at first. Olson ran through the bag in a routine play, but Harper's arm was in the basepath and took the contact from Olson.

Here is the play:

Harper returned in short order from Tommy John surgery just months ago, and the immediate concern is that he may have re-injured his UCL. At this point, nothing is known regarding the injury. The earliest we'll know if there is damage serious enough to keep him out of the game would be this evening after imaging, but it's likely to be tomorrow or later before Philadelphia gets any meaningful information.

Bryce Harper injury would be terrible timing for Phillies

UPDATE 11:05 p.m. ET: Bryce Harper is back on the field for the top of the ninth inning.

If Harper is injured enough to have to miss time, it would surely be miserable timing for the Phillies, who need to win eight more games to secure a World Series title if they win Game 4 against the Braves.

The extent of the injury, as mentioned, is currently unknown. But if Harper re-injured his UCL, there's a possibility he could still play as DH, depending on the severity of the injury. His spots at first base are already designed to limit his use of the elbow compared to the stress throwing from the outfield would put on it.

Unfortunately for Philly, even in that case there aren't great options at first base. Rhys Hoskins is out with an ACL injury. Alec Bohm has also played some first base this year. Such a move would also necessitate Kyle Schwarber surrendering the DH role and re-entering the outfield.