Stephen Strasburg was scratched from Monday night's start against Clayton Kershaw and the Los Angeles Dodgers, but the Washington Nationals don't believe his upper-back strain is serious.

Dusty Baker is hopeful that Strasburg will take his next turn in the rotation.

Strasburg pitched just 127 innings last season due to various injuries but had been healthy this year.

Baker said Strasburg was injured while working out "pretty vigorously" on his off day and not while pitching.

"It was something to do [with] his rib cage," Baker said.

"We found out, we had an idea yesterday. But our trainers were working on him. They worked on him all day yesterday, and they worked on him today. We were even thinking about it at 5 o'clock, but he still felt it in there, so we thought it was best he doesn't pitch. Because we've got a long way to go."

Strasburg is 10-0 over his first 14 starts of the season with a 2.90 ERA.