Las Vegas Raiders quarterback Jimmy Garoppolo has been ruled out for Sunday's matchup against the Chicago Bears,James Caldwell according to reports.

ESPN's Adam Schefter reported that Garoppolo will not play Sunday after sustaining a back injury early in the Raiders' 21-17 win over the New England Patriots last week. Garoppolo injured his back during the first half and was transported by ambulance from Allegiant Stadium to a local hospital to get evaluated.

Although it's not clear how many games Garoppolo will miss, head coach Josh McDaniels said earlier this week that his injury could have been worse, adding that it "seems like we’ve dodged a big bullet."

JOSH MCDANIELS:Raiders 'dodged a big bullet' with QB Jimmy Garoppolo's back injury

Either veteran backup Brian Hoyer or rookie Aidan O’Connell will start in Garoppolo's place on Sunday. Both have made an appearance this season. O'Connell started in the Raiders' Week 4 loss against the Los Angeles Chargers while Garoppolo was sidelined due to injury and Hoyer played the entire second half in their win over the Patriots after Garoppolo made an early exit.

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"The fact that we’ve played three guys already certainly doesn’t hurt," McDaniels said Monday. "It’s not ideal in terms of what you want to do, but they’ve both got some experience and they’ve both had to operate our offense in critical situations and close games. That’s helpful for them, too."

The Raiders (3-3) will not be the only team with a backup quarterback under center. Bears quarterback Justin Fields is "doubtful" to play Sunday after suffering a hand injury and undrafted rookie Tyson Bagent is expected to start for Chicago (1-5).