Packers coach Mike McCarthy said that Humphrey's sore Achilles is related to his foot injury from last year.
"I think it's just a combination of coming back off a major injury, going through his first week of camp," McCarthy said.
McCarthy said he will decide prior to the team's annual Family Night scrimmage who will not participate, though Humphrey said he would be ready and is looking forward to absorbing his first hit.
Center Scott Wells, who injured his side trunk (torso) in Friday night's practice, said if Sunday night's scrimmage was a regular season game, he could play.
"It's not that serious," Wells said. "It's more of a tolerance issue. Yeah, it hurts, but it also is early in camp, so we have time to get it right so it doesn't linger throughout the preseason and into the regular season."
Cornerback Condrew Allen left practice with a bruised knee. Others who sat out with prior injuries included defensive tackles Justin Harrell (back) and Ryan Pickett (hamstring); running back DeShawn Wynn (concussion) and cornerback Tramon Williams (hip flexor).