"I think [when] he slid into the base, he kind of jammed it a little bit," Weiss said.
"I didn't see anything when it happened, but his knee kind of stuck in the ground. I think he just landed the wrong way."
Corey Dickerson batted leadoff and played center field in place of Fowler, who started 20 consecutive games before this injury.
After going on a tear in early August, Dickerson entered Tuesday with just one hit in his last 14 at-bats, a single that eventually turned into Colorado's sixth run in Monday's victory.
Ian McCue is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.