Port St. Lucie, Fla. ? John Valentin is making a strong claim to be on the New York Mets’ opening-day roster.

Valentin, who has appeared at a few positions already this spring, played first base on Tuesday and doubled in the Mets’ 4-0 victory over the Kansas City Royals.

Jeff D’Amico, Satoru Komiyama, Bruce Chen and David Weathers combined for a one-hitter against the Royals.

Valentin, who played 10 years with the Boston Red Sox, signed with New York in January. Recovering from an injured right heel, the 35-year-old infielder readied himself for a new role during the offseason.

“I knew that this year I would have to take a step back and do something else,” Valentin said. “It’s challenging, it’s definitely challenging and I’m trying to have fun with it, I’ve always accepted challenges well.”

So far this spring, Valentin has played third base, shortstop and first base. He is also slated to play the outfield corners, Mets manager Bobby Valentine said.

Valentine was originally concerned about Valentin’s injury troubles, including a ruptured tendon in his left knee two seasons ago.

“So far I’ve liked everything I’ve seen,” Valentine said. “He’s moving better, he’s a veteran guy who has a very good idea about how to play the game.”

On Monday, Valentin started at shortstop and had a double against the Dodgers. Valentin is hitting .384 this spring.

“To get here I had to work hard, I had to make sure that when I came in here Bobby would know that I’m ready,” Valentin said. “Everybody knows that I can play if I’m healthy, so my job is to prove that I’m healthy.”

Valentin hasn’t been an everyday shortstop since 1996, but was third in fielding percentage in 1998 among AL third basemen.

He’s also played second base, but Valentine has no intentions of putting him there as Valentin already has enough learning to do at other positions.

“We still have to see more of him, we have to really see how he can stretch it out with his running,” Valentine said. “We have to make sure he’s OK, like sliding, running and scoring from second.”

Edgardo Alfonzo hit a three-run homer in the first inning to stake D’Amico to a lead.