Las Vegas Raiders quarterback Aidan O’Connell is expected to miss four to six weeks with a broken thumb on his right (throwing) hand, sources told ESPN’s Adam Schefter on Monday.

O’Connell, who wore a heavily wrapped thumb splint after Sunday’s 20-15 loss to the Los Angeles Rams, will undergo further testing on Monday.

The quarterback said Sunday he suffered a similar injury in high school.

Raiders coach Antonio Pierce had no update on O’Connell Monday afternoon. He said he wasn’t sure if the Raiders will add another quarterback as it depends on O’Connell’s status.

“Once we find out what’s going on with Aidan, I’m sure we’ll have to look at all our options,” Pierce said.

It was on the second offensive series of the day for the Raiders when O’Connell attempted a deep pass to the right side on second-and-10 and was hit by Rams safety Kamren Curl on his follow-through. With no receiver nearby, O’Connell was issued a warning for intentional grounding.

One play later, on third-and-21, O’Connell hit receiver DJ Turner for a 10-yard pickup. It would be O’Connell’s last play of the match.

“I threw it and it didn’t feel great,” he said Sunday. “I tried to hold on, but yeah, it doesn’t feel great.”

O’Connell, who replaced Gardner Minshew as starter last week, completed 6 of 10 passes for 52 yards against the Rams. According to ESPN Research, he was pressured on five of his 10 dropbacks (50%) and was 2 of 5 for 19 yards when pressured.

“Super unfortunate,” O’Connell said of the timing of the injury. “I was really looking forward to today and this opportunity, and it was definitely hard to cut it short.”

Minshew, who sat in favor of O’Connell last week, replaced O’Connell. Minshew had signed a two-year free agent contract with $15 million guaranteed and won a tight training camp battle with O’Connell. He completed a career-high 70.7% of his passes for 1,014 yards and four touchdowns in five starts, but was also picked off five times in those games.

In his final game before being benched, Minshew threw a 100-yard pick-six against the Denver Broncos in Week 5, turning a potential 17-3 Raiders lead into a 10-10 game and eventual loss from 34-18. Minshew had a career-low 40.2 QBR at the time of his benching.

Against the Rams on Sunday, Minshew was responsible for four turnovers – three interceptions and a fumble that was recovered by Curl and returned 33 yards for a touchdown – and was 15 of 34 for 154 yards and a career-low single-game passer rating of 21.0.

Minshew has thrown eight interceptions and fumbled three times this season, losing two of them. His 10 turnovers are tied for the NFL lead with Tennessee Titans quarterback Will Levis.

“I’ve never turned a ball over like that in my life,” Minshew said Sunday. “It’s very frustrating. So we just have to keep looking at it, keep studying, keep training, (have) good habits and we will find a way out.

“A little bit is aggressive with the ball. A few of them were just bad ball placement, like DJ (Turner)’s today, who just missed behind him. So a combination of things, so I have to look at it, address it and move on.”

The only other quarterback under contract with the Raiders is undrafted rookie Carter Bradley, who is on the practice squad and has yet to make his NFL debut. The Raiders also had veteran Nathan Peterman on their training camp roster for two weeks, but he is now on the Atlanta Falcons’ practice squad.

Wide receiver Tyreik McAllister would have been the emergency third quarterback if Minshew had also been injured Sunday, Pierce said Monday. Wide receiver Jakobi Meyers is the usual third quarterback, but he was inactive Sunday due to an ankle injury.