INDIANAPOLIS -- Jordan Mills' run of good health ended Thursday when the third-year right tackle failed to finish the Chicago Bears' practice against the Indianapolis Colts because of a calf injury.

With Mills out of commission, Charles Leno played right tackle on the first team for virtually the entire workout.

"[Leno] has been playing with the second team all camp, performing well, and when Jordan Mills went out, he was the logical guy to stick there," Bears head coach John Fox said.

Fox refused to say whether Leno will start at right tackle Saturday night at Lucas Oil Stadium.

"We haven't even met as a staff yet so I'd probably like to talk to them first before I talk to you guys," Fox said.

Mills is no stranger to setbacks.

Mills' promising rookie campaign got derailed in Week 17 of the 2013 regular season when he suffered a fracture in his foot during pregame warm-ups. Even after offseason surgery, Mills' foot continued to cause him problems. Mills admitted on numerous occasions that his lingering foot issue caused him to lose confidence in 2014, but he seemed in better spirits during the Bourbonnais portion of camp.

In other injury news, outside linebacker Pernell McPhee (knee) and defensive lineman Brandon Dunn (quad) also did not finish Thursday's session.

Cornerback Tracy Porter (hamstring), offensive tackle Jason Weaver, receiver Alshon Jeffery (calf), running back Daniel Thomas (knee), tight end Chris Pantale (illness) and outside linebacker Jared Allen (coaches' decision) did not participate.

The Bears will hold a closed practice Friday in Indianapolis.