Johnson was replaced in the game by Omar Vizquel, who threw out Carlos Pena at home plate to end the ninth and force extras.
Johnson has been dealing with issues in his legs for the majority of the season, but the discomfort intensified in the past seven to 10 days.
The 30-year-old is listed as day to day. He remains optimistic that he won't be forced to miss any time.
"The left leg has been sore for awhile," Johnson said. "It has been about managing it, but now when I run, it's just not loosening up.
"It's just always there. I think we'll be good, though, day off [on Thursday] and I think we've got something, we've figured it out a little, so maybe we'll have it knocked off soon. Day off should help out a lot."
Johnson is hitting .250 with eight homers and 23 RBIs in 44 games this year.