BALTIMORE — Red Sox slugger David Ortiz will have an MRI taken on his injured left wrist today in Boston.

He said he felt a “pop” when he swung at a pitch during his ninth-inning at-bat Saturday night at Camden Yards. He started treatment yesterday and was sporting a removable brace, saying he’s never had anything like it before. It’s being defined as a strain and he’s listed as day-to-day. Ortiz has injured his right wrist twice in the past, once in 1999 and again in 2001.

This time it was different. He said he could understand if he took a check-swing, but it was a full swing a “Big Papi swing.” There’s no swelling, just a “clicking” going on. Manager Terry Francona pulled Ortiz from his plate appearance and replaced him with Sean Casey. “I wanted to (finish the at-bat) ,” Ortiz said. “I couldn’t because it would have got worse. I’ve never felt anything like it before…. Hopefully it’s nothing too bad because I’m tired of (these injuries).”

He was hampered last season with a knee injury, but he had surgery during the winter and felt the effects of it earlier this year. Ortiz finally got his groove back, posting .308 average (8-for-26) over the last seven games. In his last 29 games, he’s hitting .324 with nine homers and 23 RBI.

The x-rays he had taken Saturday night were negative, but for precautionary reasons he’ll have the MRI today. He’s listed as day-to-day.

jmcdonal@projo.com