Derek Carr left the Raiders’ Week 4 loss to the Broncos with a back injury. The team initially said its quarterback had back spasms, but that wasn’t the case. On Monday, the Raiders announced that Carr has a transverse process fracture in his back. Carr is expected to miss two to six weeks to fully recover.

Carr had x-rays and an MRI, but both were inconclusive. A CT scan on Monday confirmed the fracture.

“I just got off the phone with him; he said he’s sorry,” Del Rio said Monday. “He’s a great kid, he’ll bounce back. I told him the team will take care of business while he’s healing, and just get healed up, and when he can come back, he’ll come back.”

What’s a transverse process fracture? A transverse process is a small bone that sticks out on either side of the vertebrae. It’s not a risk to Carr’s spinal health and the injury isn’t serious in the grand scheme. The biggest issue for Carr will be pain tolerance.

If you were watching the Raiders game when Carr was injured, you probably noticed that Tony Romo was immediately concerned about the injury.

Romo had good reason to be: He had two of them at the same time in 2014. Cam Newton also suffered the same type of fracture when he was in a car accident in 2014.

What does this mean for the Raiders? It depends on how long Carr is out. Carr was sidelined last year after suffering a fractured tibula in Week 16, and Matt McGloin and Connor Cook weren’t able to do enough to prevent an immediate playoff exit with a 27-14 loss to the Texans. Oakland lost both games that Carr missed last year.

Now EJ Manuel will take Carr’s place. Manuel entered the game on Sunday when Carr was injured and he completed 11 of 17 passes for 106 yards and one interception.

Del Rio was pleased with Manuel’s performance.

“I thought EJ gave us a chance there at the end,” Del Rio said. “He did some things really well, and so there’s some definite positive, encouraging signs, that we can build on.”

If Carr just misses two weeks, Manuel may be just fine against the Ravens and Chargers. But if he misses more time, the Bills and Chiefs will be challenges for Manuel and the Raiders.

In 10 games for the Bills last season, Manuel threw for 1,972 yards with 11 touchdowns and nine interceptions.