CHICAGO — The New England Patriots won their fourth consecutive game Sunday afternoon but might have lost a major piece of their offense.

Rookie running back Sony Michel, who had racked up 316 rushing yards and four touchdowns over his previous three contests, exited the Patriots’ 38-31 victory over the Chicago Bears after suffering what appeared to be a significant knee injury on the first play of the second quarter.

Michel’s knee twisted violently beneath Bears defensive end Bilal Nichols after a routine handoff, causing him so much pain he dropped the ball. He needed to be helped off the field, then quickly was shuttled off toward the locker room on a cart after spending a few minutes in the sideline medical tent.

The Patriots officially ruled Michel out after halftime, and he finished with 22 yards on four carries, plus a 13-yard reception.

“Losing Sony was tough,” quarterback Tom Brady said after the game. “We all hope he’s OK. He’s doing a great job for us.”

The Patriots withstood Michel’s injury thanks to workmanlike ball-carrying efforts by James White (11 carries, 40 yards) and Kenjon Barner (10 carries, 36 yards), both of whom set single-game career highs for rushing attempts. But moving forward with just those two — a pass-catching specialist and a career special teamer — certainly is not a sustainable strategy.

So, what’s New England’s next move?

Part of that depends on the severity of Michel’s injury; he’s reportedly scheduled to undergo an MRI on Monday. Even if it’s revealed to be minor, though, the Patriots should seriously consider adding another running back to their roster this week. Given Michel’s injury history — he already missed the entire season and Week 1 with a knee injury and dealt with knee issues in college, too — carrying just three backs was a dicey proposition to begin with.

The Patriots should be able to activate Rex Burkhead off injured reserve before the end of the season, but he’s not eligible to return until Week 13 at the earliest. In the meantime, they have a few options to address their need for depth at the position:

1) Sign Kenneth Farrow off the practice squad
This wouldn’t be the splashiest move, but the 5-foot-11, 216-pound Farrow has more size than White (5-10, 194) or Barner (5-9, 190) and does have some NFL experience, having carried the ball 60 times in 13 games for the San Diego Chargers in 2016. He’s in his second stint on the Patriots’ practice squad this season and also spent a week on their 90-man roster late in the preseason.

2) Sign a free agent
Mike Gillislee, who lost his Patriots roster spot to the now-injured Jeremy Hill this summer, is the obvious choice here. The New Orleans Saints cut him more than two weeks ago, though, and while there was contact between the Patriots and Gillislee’s camp, a reunion has yet to materialize. Perhaps that would change if Michel is sidelined for the foreseeable future.

Other currently available veteran backs include Orleans Darkwa, Charcandrick West and Andre Ellington, all of whom have worked out for the Patriots within the past two months. A deeper look yields names like Christine Michael, who visited the Patriots before the 2017 season, and DeMarco Murray, who announced his retirement in July.

3) Swing a trade before the Oct. 30 deadline
If the Patriots can’t find anyone they like in free agency, a trade is always a possibility.

The Boston Herald’s Kevin Duffy pointed to Ameer Abdullah of the Detroit Lions as a back who could be dealt because of the limited role he currently has behind rookie Kerryon Johnson, Theo Riddick and LeGarrette Blount. Abdullah, a 2015 second-round pick, has carried the ball just once all season.

Abdullah is an extreme case, but a quick survey of NFL rosters shows a few other running backs who fall into this same category, including Denver’s Devontae Booker (behind Royce Freeman and Phillip Lindsay), Carolina’s C.J. Anderson (behind Christian McCaffrey), Oakland’s DeAndre Washington (behind Marshawn Lynch, Doug Martin and Jalen Richard), Tampa Bay’s Jacquizz Rodgers (behind Peyton Barber and Ronald Jones) and San Francisco’s Alfred Morris (behind Matt Breida and Raheem Mostert).

It’s unclear whether the Patriots would be interested in dealing for any of those players, though they reportedly expressed interest in Anderson when he was a free agent in 2016. Morris, who is on a one-year, $790,000 contract with the Niners, is an interesting candidate given the Patriots’ positive relationship with John Lynch and Kyle Shanahan.

The trade deadline’s biggest name, of course, is disgruntled Pittsburgh Steelers star Le’Veon Bell, but his price tag just seems too steep for the Patriots, both in terms of contract value and trade compensation. (According to Albert Breer of The MMQB, the “floor” for any Bell return would be a second-round pick.)