Strasburg has a discussion with pitching coach Steve McCatty before being removed from the game the Atlanta Braves at Turner Field on May 31.
The Washington Nationals have placed Stephen Strasburg on the 15-day disabled list because of a strained muscle in his back.
The San Diego native skipped a scheduled bullpen session Wednesday.
The session was supposed to determine whether he could make a start on Saturday.
Strasburg was removed after two innings when he showed obvious discomfort during Friday's game against the Atlanta Braves.
The Nationals said the next day that Strasburg had a "slight strain" to the lat. The team was hoping he would not miss a start, although he was moved back two days in the rotation to give him time to heal.
Manager Davey Johnson said a pitcher will be promoted from Triple-A Syracuse to start on Saturday.
The San Diego State University alum is 3-5 with a 2.54 ERA.