"We don't know how it happened," Thomson said Friday. "We don't know long it's going to be. But we'll re-evaluate tomorrow."
Suárez is 2-6 with a 3.88 ERA in 17 starts.
The Phillies, who had off days Monday and Thursday this week, will start right-hander Zack Wheeler against Washington in Sunday's Little League Classic in Williamsport, Pennsylvania, on regular rest. Aaron Nola will start Monday when Philadelphia returns home to face San Francisco.
Thomson said there was not much immediate concern this could be a long-term issue for Suárez.
"A lot of times your legs get aggravated on that turf so I'm hoping that's all it was," Thomson said.