"We did not even bring him out today," Kubiak said of Johnson following Wednesday's practice. "We weren't going to run him today. It's going to be day-to-day."
Johnson pulled up in the third quarter of Sunday's 17-10 win over the Atlanta Falcons while chasing a deep pass from rookie quarterback T.J. Yates. The five-time Pro Bowl selection was playing his second game after missing the previous six with a right hamstring injury that required minor surgery in October.
An MRI exam Monday revealed that this hamstring injury is not as bad as the previous one, as was expected. On Wednesday, Kubiak said he feels "fortunate" that Johnson's latest injury wasn't more severe.
Johnson has 31 catches for 471 yards and two touchdowns in six games this season.
Kubiak said Brian Cushing was held out of practice because the linebacker is "beat up." Cushing left last Sunday's game with a right leg injury but later returned.
Kubiak confirmed the additions of quarterback Jeff Garcia and punter Matt Turk. Garcia is expected to serve as Houston's third-string quarterback behind Yates and veteran Jake Delhomme.