New York ? The Yankees placed rookie outfielder Juan Rivera on the 15-day disabled list Sunday with a fractured right kneecap, and closer Mariano Rivera could follow in the next few days because of a strained right groin.

The All-Star reliever was not available to pitch Sunday, and Steve Karsay saved New York’s 4-2 victory over the San Francisco Giants.

Yankees manager Joe Torre said Mariano Rivera, who is not related to Juan, will also miss a three-game series against Arizona that begins tonight. But Torre wasn’t sure if his closer would be put on the DL.

“Right now I think we’re going to give it three or four days and see what happens,” Torre said.

Juan Rivera crashed into a golf cart while shagging flies during batting practice Saturday. He did not play in the last two games of the series against San Francisco, and was placed on the disabled list retroactive to Saturday.

It’s been a wild week for the 23-year-old rookie, who was called up from Triple-A Columbus on Wednesday and handed the everyday job in right field because of poor production from Shane Spencer and John Vander Wal.

Juan Rivera went 1-for-6 in two big league games.

The Yankees will call up outfielder Marcus Thames to take his spot on the roster. Thames was batting .222 with six home runs and 20 RBIs in 46 games at Columbus.

Vander Wal started in right field Saturday and Spencer on Sunday. They each went hitless.

Before Juan Rivera’s recall, there had been speculation that the Yankees would make a run at trading for a big hitter like Florida’s Cliff Floyd. Now, they might be even more inclined to do that.

New York probably won’t make a move to replace Mariano Rivera on the pitching staff, because Andy Pettitte is scheduled to come off the disabled list and start Friday night against the New York Mets.