The University of Washington product did not practice all week. Butler's listed as doubtful on San Diego's injury report. Andrew Gachkar started in place of Butler last week against Indianapolis.
The Chargers also could be without the team's main punt returner and slot receiver. Eddie Royal did not practice all week because of a toe injury he suffered against Indianapolis, and is listed as questionable. Royal wore a protective boot on his injured foot while watching practice.
"I've been here about two weeks now, so I've got the playbook down," Hawkins said about the potential of more playing time. "Now it's time to go out there and play fast."
Hawkins also will handle kick return duties for a second straight week. Allen will handle punt return duties if Royal can't play. The rookie out of Cal became only the second rookie in team history to post back-to-back, 100-yard receiving games after finishing with eight catches for a game-high 107 yards against Indianapolis last week. Don Horton was the last to do that for the Chargers in 1960.
Chargers offensive coordinator Ken Whisenhunt said that Allen should have no problem moving inside and giving San Diego reps at slot receiver.
"Keenan got a lot of work for us in camp at that position," Whisenhunt said. "So obviously he has an ability to do that. And he played there a lot in college."
Offensive lineman Chad Rinehart did not practice for a fourth straight week because of a toe injury, and has been ruled out for Sunday.
Outside linebacker Jarret Johnson (hamstring) and offensive lineman Stephen Schilling (neck) were limited participants in practice Friday, and are listed as questionable.
"We're going to do what's best for the team, and what's best for him as we go forward," San Diego coach Mike McCoy said, asked about Johnson's availability on game day. "We'll take it one day at a time, and see how he feels on game day."