CHICAGO -- Bears quarterback Justin Fields dislocated his right thumb Sunday and is doubtful to play against the Las Vegas Raiders in Week 7, coach Matt Eberflus said Monday.
Fields suffered the injury in the third quarter of the Bears' 19-13 loss to the Minnesota Vikings. X-rays were negative, but he had an MRI on Monday.
"There's no timetable right now," Eberflus said. "It's really going to come down to grip strength. There's natural swelling that occurs with this injury, so we should know more at the end of this week."
Eberflus said the Bears anticipate knowing whether Fields will need surgery on his thumb in a few days. The Bears coach said he did not get any feedback on what the MRI revealed and reiterated that Fields' ability to grip the ball will be paramount in determining next steps.
Fields was working with athletic trainers at Halas Hall on Monday, and Eberflus said he just wants to "give it time" for the swelling to go down.
"It doesn't look like it's a negative thing," Eberflus said when asked if Fields had any torn ligaments, "but we'll see where it is."
Fields injured the thumb after landing on his right arm while being sacked by Vikings defensive end Danielle Hunter on Chicago's first drive of the third quarter. As Fields was falling to the ground, he tried to flip the ball in the direction of running back Darrynton Evans.
After a visit to the injury tent, Fields walked back to the locker room with a towel over his right hand. He was initially listed as questionable to return and ruled out shortly thereafter.
Rookie QB Tyson Bagent made his NFL debut in place of Fields on Sunday and completed 10 of 14 passes for 83 yards and interception and had a 1-yard QB sneak to cap Chicago's only touchdown drive.
"I thought he really worked through it," Eberflus said of Bagent. "Obviously the first series or so wasn't ideal. I think that you give him credit. He's a backup quarterback, a young guy, I think he came in there and had poise.
"... He showed that during that touchdown drive. There were a lot of good things that come out from Tyson in that game."
Bagent, an undrafted free agent from Shepherd University, holds the NCAA record for all-time touchdown passes (159) and is the Division II record-holder for all-time passing yards (17,034) and total touchdowns (171). He signed with Chicago in May and beat out current Browns quarterback PJ Walker, who was with the Bears this offseason, for a spot on the initial 53-man roster. Veteran backup Nathan Peterman is the third QB on Chicago's active roster and was the emergency quarterback for the Vikings game.
Eberflus said he did not believe the Bears would need to simplify their playbook for Bagent if he starts in place of Fields on Oct. 22.
"We're always prepared for that, for sure," Eberflus said. "It's one play away. You're one play away from being in there, and Tyson's earned that spot with his opportunity that he's created himself. And we're certainly gonna do that going forward for sure."
The Bears coach provided two additional injury updates on Monday. Eberflus said right guard Nate Davis suffered a high ankle sprain against the Vikings and will not play against the Raiders. Cornerback Terell Smith, who was downgraded to out last Friday with an illness, will be sidelined "three to four weeks" with mononucleosis, Eberflus said.