Strasburg scratched with upper back strain, Petit to start

LOS ANGELES - One of the season's most anticipated pitching matchups won't happen after all.

The Nationals were forced to scratch Stephen Strasburg from tonight's outing against Clayton Kershaw and the Dodgers with an upper back strain. Reliever Yusmeiro Petit will now start in his place, facing a stiff challenge on short notice.

The change was announced less than 90 minutes before first pitch at Dodger Stadium. Strasburg had arrived at the ballpark earlier in the afternoon, walking into the visitors' clubhouse without showing any obvious symptoms of a problem.

Strasburg did deal with nagging upper back and neck injuries during most of the first half of the 2015 season, and last fall he had minor surgery to remove a non-cancerous growth from his back. But the right-hander had shown no ill effects of that ailment since.

In fact, Strasburg has been among the most dominant pitchers in baseball over the last calendar year. In 27 starts since returning from the disabled list for that neck/back injury, he is 18-2 with a 2.37 ERA. Only Kershaw and Cubs ace Jake Arrieta own better ERAs in that span.

That's what made tonight's series opener intriguing to so many. According to STATS, LLC., this would have been the first matchup of 10-game winners this early in a season in more than 100 years.

"This is what it's all about," Nationals manager Dusty Baker said this afternoon, before Strasburg was scratched. "This is fun. This is what I grew up as a kid. You watch (Juan) Marichal and (Sandy) Koufax, you watch (Don) Drysdale and Gaylord Perry, you watch (Bob) Gibson and Ferguson Jenkins ... Nolan Ryan and Don Sutton. This is what it's all about: pitching matchups. I was excited coming to the park today. I was excited with the thought of it."

There was no immediate word about the severity of Strasburg's injury or how much time he might need to recover, but this comes at a particularly inopportune moment for the Nationals. With closer Jonathan Papelbon on the disabled list with a strained intercostal muscle, the club's bullpen has been stretched thin, with several relievers pressed into new roles.

That includes Petit, who typically is a long reliever but was needed to pitch in a save situation over the weekend in San Diego. With Petit unlikely to be able to give his team a full-length start tonight, the Nationals probably will need to use up much of their bullpen to get through this game.