NFL Network Insider Tom Pelissero reported that Allen is unlikely to play on the short week, but there is optimism after tests that his injury isn't a long-term issue, per sources informed of the situation.
Head coach Brandon Staley, speaking to the media later on Tuesday, said Allen was going to take some time with his hamstring and it didn't look good for him in terms of playing against the Chiefs, but wouldn't rule anything out just yet.
Allen missed the second half of the Chargers' Week 1 win over the Las Vegas Raiders after suffering the injury. He caught four passes for 66 yards, including a 42-yarder, before exiting.
As L.A. travels to K.C. on a short week, it's not surprising Allen will miss Thursday's game. With extra time before the Chargers face the Jaguars on Sept. 25, the hope is the star wideout can return swiftly.
The Chargers receivers who do suit up Thursday likely will be facing a depleted Chiefs secondary. Kansas City placed first-round rookie cornerback Trent McDuffie (hamstring) on injured reserve.