LOS ANGELES -- Rams defensive lineman Ethan Westbrooks was arrested over the weekend in Kern County, California, for allegedly possessing a handgun that was not registered to him, ESPN confirmed Monday.

Westbrooks was initially pulled over for speeding Friday night, and the officer found a handgun inside the vehicle that was loaded with 13 rounds of ammunition. Records later revealed that the handgun was reported stolen in 2009, according to records from the California Highway Patrol.

The Rams player was booked in Kern County Jail in Bakersfield, California, located roughly 115 miles north of Los Angeles, and later posted bail. He practiced with the team in Thousand Oaks, California, on Monday afternoon.

Westbrooks, whose arrest was first reported by the Southern California News Group, was booked on five felony charges: receiving stolen property, carrying a loaded firearm, carrying a stolen loaded firearm, grand theft of a firearm and possessing a high-capacity magazine.

He has an arraignment scheduled for Oct. 5.

Westbrooks wasn't able to go into detail about the arrest because it's a pending legal matter. The 26-year-old said he spoke to Rams coach Sean McVay about it on Monday and was told the organization will be supportive. Westbrooks simply called it "a bad situation."

Asked if he would play Sunday, and if everything will remain normal on the field, Westbrooks said, "It's been normal so far. As far as Sunday, I honestly can't tell you."

An undrafted free agent out of West Texas A&M, Westbrooks has spent the past four years with the Rams and has racked up five sacks while playing an increased role since the start of the 2015 season. The Rams recently extended Westbrooks' contract through 2018.

Westbrooks was arrested on suspicion of domestic violence in Sacramento, California, in March but was never charged.