Mets lefty Robert Carson is day-to-day with a triceps tendon strain, according to the team. The injury was originally believed to be to his elbow, but an MRI revealed Tuesday that it was the triceps. Carson had an X-ray following Tuesday's game and it came back negative.

"A real big sigh of relief," Carson said Wednesday afternoon. "I was a little nervous yesterday, last night, coming out of the game. It was a different feeling I've never felt before. First thing that came to my head was surgery. So I was a little scared but when I saw the doctor today and found out it was just a triceps tendon strain it was a big sigh of relief."

Carson believed he had hyperextended his elbow while pitching during the seventh inning on Tuesday night. He felt it stretch and it was uncomfortable, and after his velocity dipped on the next few pitches, he knew something was wrong. The team removed him from the game and the rookie is not sure if that was his final appearance of the season.

"As of right now, all I know is it's going to be day by day," Carson said. "Going to do a little treatment and then see what happens. I'm the type that I want to play but right now I'm taking it day by day and get some treatment every day and go from there."

Carson was a starter in the minors last season but the team converted him to a reliever and he made 41 appearances in Double-A and Triple-A this year. He had a brief stint with the team in April and May, but has been with the Mets since the end of August and has pitched well. He has a 4.73 ERA.

Mets manager Terry Collins praised Carson for his work out of the bullpen and was also relieved that the reliever only had a strain.

"I know he was extremely scared and nervous last night that this could have been a severe injury. It's not, sounds great, rest will be fine, so I know that in the Carson household, it will go heading into a very good winter," Collins said before the Mets faced the Pirates. "Another guy that took a huge step forward from where he was in the beginning of the season, spring training. The guy who was going to have a new role and ended up pitching in the major leagues at the end of the season and doing a good job. We're very excited about the future ahead."

While Carson isn't sure if he'll be able to help the team again this year, he's heading into the offseason trying to make sure he's on the Opening Day roster in 2013.

"I'm very happy with the year I had this year," Carson said. "I don't want it to end like this, I wanted to finish strong. Injuries happen. I think I'm going into the offseason and really work hard and try and come back and be here next year and help the team for 162 games next year."