COSTA MESA, Calif. -- The Los Angeles Chargers exited a bye week expecting to be healthier than when they entered it.

No such luck.

The Bolts (4-3) will be without their top two receivers in a Week 9 matchup against the Atlanta Falcons (4-4) on Sunday at Mercedes-Benz Stadium.

Keenan Allen has been ruled out because of a left hamstring injury, and Mike Williams also has been ruled out because of a high ankle sprain.

Wide receiver DeAndre Carter, also a return specialist, is listed as questionable after coming down with an illness Friday. And the Bolts' injury issues coming off an open date don't stop there.

With starting kicker Dustin Hopkins sidelined since Week 7 because of a right hamstring injury, the Bolts turned to practice-squad kicker Taylor Bertolet. However, Bertolet suffered a quadriceps injury during practice Wednesday and the Chargers have since signed Cameron Dicker to the practice squad.

Dicker, a rookie who converted 2 of 2 field goal attempts for the Philadelphia Eagles in Week 5, is expected to kick Sunday.

And tight end Donald Parham Jr., coming off being sidelined because of a concussion in Week 7, is now again dealing with a hamstring injury that kept him sidelined the first four games of the season.

Parham has been ruled out.

"Our guys know that's part of the game," coach Brandon Staley said of the numerous injuries. "You've got to stick together through situations like this."

After spending five games on the sideline, Allen appeared to be on the mend from the nagging issue when he played in the first half of a 37-23 loss to the Seattle Seahawks in Week 7 and caught two passes for 11 yards.

But Allen said he reaggravated the injury while training during the bye week. "I don't think it was a restrain or anything," Allen explained earlier this week. "It is just some more scar tissue that is trying to break off, and whenever it is ready to heal, just got to let it do its own thing."

With the absences of Allen and Williams, and with uncertainty around Carter, the Chargers are expected to turn to Joshua Palmer, who did not play in Week 7 because of a concussion, Michael Bandy and Jason Moore Jr.