Rivera threw 20 pitches in live batting practice to two hitters, Kyle Roller and Rob Segedin, and afterward proclaimed himself "excited'' to be back on the mound.
"Not nervous, excited,'' the 43-year-old Rivera said after the brief session. "This is the first BP I'm throwing in almost a year, so I'm real happy with the results.''
Rivera's 2012 season ended May 3 in Kansas City when he tore the anterior cruciate ligament in his right knee shagging fly balls during batting practice. He had thrown several bullpen sessions in camp and has taken part in all the pitchers' fielding drills but had yet to face hitters in a live situation.
And he approached it with enthusiasm, calling his first two pitches strikes from the mound and shouting "There you go!'' to Segedin as he lined the third pitch into center field.
"Basically, I just wanted to see the hitters, seeing how they swing at the ball and how they react to the pitches,'' he said.
As for his stuff, Rivera said, "It will get better. As long as I keep throwing, it will get better.''
Rivera's main concern, however, is not with his pitches so much as his ability to come off the mound quickly in game situations on his surgically repaired knee.
"The big thing now is to do the real thing, covering first base, fielding bunts, all that stuff,'' he said. "My command I don't worry about. That's one thing I never worry about. It didn't take no vacation. It's still there. It hasn't gone nowhere.''
Rivera, the all-time saves leader with 608, generally does not appear in exhibition games until the second half of the spring and usually throws between six to eight innings to get ready for the season.
This spring, however, he may start earlier and throw more to compensate for his long period of inactivity.
"Maybe another one or two more BPs and I'll be ready (to pitch in a game),'' he said. "I don't know. We have a long time. I'm not trying to rush at all. It felt good to see guys up there again, but the one thing I want to do is get in a real game and see how everything responds.''