Johnson said Strasburg is not more injury-prone than other pitchers. His injuries are simply more scrutinized because of his 2010 Tommy John surgery and status as the team's top starter.
"I think it's who he is," Johnson said. "He's our No. 1 pitcher. Anything that goes on with No. 1 pitchers, high Draft pick, No. 1, there's just a lot of interest. Same thing with [Bryce] Harper. Anything happens to him, everybody analyzes it every which way. It's just part of it."
Strasburg did some light running and played catch on flat ground on Friday without any issue. If the tightness returns before Saturday's game, Johnson said Dan Haren has volunteered to start on short rest.
Tom Schad is an associate reporter for MLB.com. Follow him on Twitter @Tom_Schad This story was not subject to the approval of Major League Baseball or its clubs.