Soriano hurting, pushed back to Saturday (plus Rivero, Duke, Kimball notes)

VIERA, Fla. - Closer Rafael Soriano, less than a day removed from a root canal to treat an infected wisdom tooth, will not pitch as scheduled today against the Tigers. "He's recovering from a long day in the dentist's chair. ... He'll be pitching tomorrow," manager Davey Johnson said. "Talking to him earlier today, he's not feeling ready to go." Johnson said the delay won't affect his plans to pitch Soriano in back-to-back games by the end of spring training. While Soriano's a lock to make the 25-man roster out of camp, the Nationals seem prepared to lose infielder/outfielder Carlos Rivero, who has hit just .171 in spring training but has impressed the club with his versatility and approach at the plate. General manager Mike Rizzo said it's doubtful that Rivero will break camp with the Nats. Because he is out of minor league options, Rivero would need to pass through waivers in order to be farmed out to Triple-A Syracuse, and that seems unlikely. "It looks like he's not making our 25-man roster," Rizzo said. "We'll know what other teams think of him by the fact that he either gets through (waivers) or he doesn't." Despite the fact that he's worked to a 5.06 ERA in six spring outings, Zach Duke's roster spot isn't in jeopardy, Johnson said. Johnson said there are reasons why Duke has struggled. "Sometimes he's had too much rest, sometimes he's still just trying to get arm strength," Johnson said of Duke. "He still hasn't used all his pitches yet. I think last time he only threw one changeup. But he's fine. I'm not worried about him." Duke will function as a left-handed long man out of the 'pen, and he's currently the only lefty in an all right-handed bullpen. Johnson likes to have both left- and right-handed long men, and Duke and Craig Stammen will fill those roles. Johnson was scheduled to watch right-hander Cole Kimball throw a bullpen session before today's game. Kimball has been bothered by tightness in his back and has not pitched since March 13, but the Nationals are hoping to get him in a Grapefruit League game sometime in the next few days.