MESA, Ariz. — The ninth inning just got a little more interesting for the Cubs.
Right-hander Pedro Strop, their presumptive closer for the start of the season, was diagnosed with a mildly strained right hamstring after having an MRI exam Monday.
Strop hurt the hamstring on his final pitch Saturday against the Angels, which resulted in an inning-ending out. He reported the pain after getting back to the dugout.
As he did in the second half of last season, Strop was expected to fill in for sidelined closer Brandon Morrow in the first month while Morrow continues his rehab work from surgery on his right elbow in November.
‘‘According to the MRI, it was barely noticeable, so we don’t think it’s going to be anything horribly wrong,’’ manager Joe Maddon said. ‘‘But we don’t know for sure. We’d like to think we’ll be able to get him ready for the beginning of the season. If not, maybe shortly thereafter.’’
Strop is expected to play catch regularly while he recovers to keep his arm in shape. And team officials hope he’ll be able to throw from a mound again in about a week, which might give him enough time to avoid the injured list when the season opens.
‘‘It’s something we caught quickly,’’ Maddon said. ‘‘I can’t emphasize enough that it doesn’t look bad, but you don’t push a guy like that right now.’’
The Cubs break camp after their exhibition game March 26. The regular season opens two days later in Arlington, Texas.
Strop finished last season sidelined with an injured left hamstring.