It is unknown whether Littleton contracted the virus or was near someone who tested positive for COVID-19.
As a precautionary move, Littleton is considered "high risk" and needs to be quarantined for a few days and can not return to the team until he tests negative on three consecutive tests.
The Raiders have yet to rule out Littleton, so if everything goes well, there is a chance he could return to the team right before Sunday's game against the Denver Broncos.
After spending his first four seasons with the Rams, Littleton hit the free-agency to sign with the Raiders later, making him one of Las Vegas' top free-agent signings this offseason.
The Raiders brought him in to add depth and improve the linebacker corps, which has struggled over the last few years.
Since his arrival in Sin City, Littleton has started eight games and recorded a total of 48 tackles, 31 solo and 17 assisted, with no sacks, no inceptions, and no force fumbles.
Not quite the production to his previous years in Los Angeles, where he recorded over 100 tackles the last two years.
The transition to Las Vegas might not have gone as planned. The COVID pandemic has resulted in the cancellation of offseason mini-camps and preseason games.
It is not the first time the Raiders have sent a player to the COVID-19 list as a precautionary move. As the Raiders sent their entire offensive line before their game against the Tampa Bay Buccaneers after having close contact with tackle Trent Brown, who tested positive for COVID-19
Littleton will join Brown on the COVID-19 lists until he clears.
If he misses Sunday's game, linebacker Raekwon McMillan and Nicholas Morrow have stepped in quite well over the last few games.
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