Strasburg to miss Friday start with back issue

Stephen Strasburg, plagued by injuries for much of the season, won't make Friday's scheduled start.

The Washington Nationals right-hander will be replaced by Tanner Roark when the team hosts the Atlanta Braves, manager Matt Williams said Wednesday.

Strasburg was pulled from Sunday's start against the Miami Marlins after just four innings and 60 pitches due to discomfort in his upper back.

"It's just a little bit of back tightness," Strasburg told reporters after leaving Sunday's game. "It's something that I kind of dealt with in the middle of the year. It's got some sort of little ball that's in the back there that I can't really figure out what it is. Sometimes it gets upset."

The 27-year-old played catch Wednesday and is scheduled for a bullpen session on Thursday.

Strasburg is 8-6 with a 4.35 ERA in 18 starts, having missed time with an oblique strain in July.