GREEN BAY, Wis. -- The new backup for Green Bay Packers quarterback Aaron Rodgers is a little hobbled.
Second-year pro Brett Hundley has an ankle injury that kept him out of practice a second straight night Thursday.
Rodgers also didn't practice, given the night off for rest.
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Hundley's injury, which happened in practice Monday, could impact Green Bay's plan for the Hall of Fame game against the Indianapolis Colts in Canton, Ohio, on Sunday.
"I think you have to be ready for the alternative," coach Mike McCarthy said before Thursday's practice.
McCarthy has been mum about playing time for the Packers first preseason game, saying those decisions would be made when he meets with his staff Friday morning.
With Rodgers unsure earlier in the week about how long he would play, if at all, Green Bay could turn to a pair of undrafted rookies to operate the offense against a Colts team that plans to play all of its available players.
Joe Callahan and Marquise Williams, the unheralded newcomers behind Rodgers and Hundley on the depth chart, apparently were a focal point in the Packers' preparations Thursday for the game.
"The two young quarterbacks were going to play a lot anyway going into it, and the game plan for the offense will reflect that, and that's part of the reason why we started working on that today in the individual meetings," McCarthy said. "That's the way it goes. It's pro football."
Plus, the Packers have an extra fifth preseason game this summer, so that could influence how playing time is divvied up early on, especially at quarterback.
Hundley assumed the No. 2 job after veteran Scott Tolzien signed with the Colts in the offseason. Hundley didn't see any in-season action as a rookie, but the fifth-round draft pick from UCLA posted big passing numbers in the preseason.
The Packers signed Callahan and Williams as undrafted free agents in May out of Wesley College and North Carolina, respectively.
After throwing for an NCAA Division III-record 5,063 yards and 55 touchdowns for Wesley last season, Callahan is excited for his first pro game.
"Yeah, first time, on national TV, so this will be pretty cool," he said. "It's something that we've been working toward all summer."
NOTES: RB Eddie Lacy didn't practice Thursday. He dropped out of practice the previous night with an ankle injury. ... DT Mike Daniels returned to practice after missing a day for a personal matter. LB Jake Ryan remains out with a hamstring injury. Rookie T Kyle Murphy is sidelined because of a concussion.