While the rest of his teammates should come back from a bye week refreshed, Los Angeles Chargers wide receiver Keenan Allen is feeling anything but. 

Allen, who has only suited up for two of his team's seven games this season, experienced a setback with his injured left hamstring during a training session and may not be healthy enough to play on Sunday against the Atlanta Falcons. 

''I don't think it was a re-strain or anything. Just some more scar tissue is trying to break off,'' Allen said. ''Whenever it's ready to heal, just let it do its own thing.'' 

Allen injured his hamstring in the season opener and missed the next five games before returning for a Week 7 matchup against the Seattle Seahawks. He played 23 first-half snaps against the Seahawks and finished with two catches for 11 yards. 

''I felt great. It wasn't like training camp,'' said Allen on how he felt during the game. ''I definitely felt ready to play.'' 

After missing practice on Monday and Wednesday, Allen is questionable for Sunday. He wouldn’t put a timetable on his return but said that he did not want to come back until there was absolute certainty in his health. 

"I definitely don’t want to do the halfway thing again," he said. "Just want to come back 100 percent and not be worried about it."

Allen’s absence Sunday would loom even larger because the Chargers could be without receivers Mike Williams (ankle) and Joshua Palmer (concussion protocol).  

With all the injuries to receivers, Austin Ekeler leads NFL running backs with 53 receptions. It is only the third time a running back has at least 50 catches through his team's first seven games.

Thursday night’s marquee matchup between the Los Angeles Chargers and Kansas City Chiefs features two potent offenses, but one team will be decidedly short-handed with decorated Chargers wide receiver Keenan Allen ruled out due to a hamstring injury.

Allen was forced to leave the Chargers’ Week 1 24-19 win over the Las Vegas Raiders in the first half after he had four receptions for 66 yards. Allen said he felt a slight pull, and the hamstring tightened after he planted his foot to the turf during the second quarter.

Coach Brandon Staley on Tuesday said Allen's injury ''is going to take some time''.

Without Allen, fellow receivers Mike Williams and Joshua Palmer figure to assume enlarged roles, with DeAndre Carter also likely to see increased playing time. Both Palmer and Carter had three catches against the Raiders.

Allen has been mostly durable during his 10-year career and has appeared in 16 games in four of the previous five seasons. The only significant time he missed was after he tore his ACL in the opening week of the 2016 season.

The 30-year-old Allen has caught at least 95 passes each of the past five years, tied for the second-longest streak in NFL history. He leads the league in catches over the past five seasons, where he has posted at least 1000 receiving yards in each and is a five-time Pro Bowl selection.