TAMPA, Fla. -- Yankees closer Mariano Rivera has reached a decision if 2013 will be his final season and plans to make an announcement before Opening Day.

"Yes, I have," Rivera said. "I won't give it up until I'm ready for that. I will tell you guys when it is the right moment."

Rivera, 43, took part in the first official workout for Yankees pitchers and catchers on Wednesday, wearing a light brace on his surgically repaired right knee.

Grinning often as he went through the usual spring paces, Rivera threw a bullpen session with catcher J.R. Murphy and did not appear to be limited in any way.

Rivera also took pitchers' fielding practice, including repeatedly breaking from the mound to receive throws at first base.

"This was the first time that I've thrown the first day of Spring Training. It was good," Rivera said. "I needed to do this. I need to be on the field as much as I can and stay on the field."

Rivera was limited to just nine appearances last year with the Yankees, his season cut short by a torn anterior cruciate ligament on May 3. The all-time saves leader said he expects a full return to form.

"Definitely. I always demand myself that," Rivera said. "I'm looking for that. Otherwise, I wouldn't be here."

Rivera has spoken openly about retirement in past seasons, and he enjoyed parrying with the media last spring by dropping hints that he was intending to make 2012 his last season.

Rivera has said that his plans were altered by the injury, which he suffered while shagging fly balls during batting practice in Kansas City. Rivera said that the injury will not alter his pregame routine.

"I don't want to change," Rivera said. "I will do whatever it takes to be myself again. I don't want to be someone that I'm not. I have to be careful -- yeah. I'm always careful."

With a decision about retirement seemingly in the works, Rivera said that the only delay is that he needs to tie up some personal loose ends before making a public announcement.

"Don't worry, the time will come," Rivera said. "You guys have been patient enough. Another day or week, it won't hurt."