A transverse process fracture is the same injury Tony Romo suffered that opened the door for Dak Prescott.
EJ Manuel moved the team well late in the Denver game when he was forced into action.
Oakland Raiders quarterback EJ Manuel (3) throws a pass against the Los Angeles Rams in the third quarter at Oakland Coliseum.
And then come the now undefeated Kansas City Chiefs for a Thursday night game. The biggest issue for Carr will be pain tolerance.
Manuel started just three games the past two seasons for the Bills and will be seeking his first win as a starter on Sunday against Baltimore since beating Miami 29-10 on September 14, 2014.More news: Derek Carr should easily beat six weeks, could return in two
More news: Donald Trump tells Rex Tillerson North Korea negotiations are "waste of time"
More news: Vikings diagnose Dalvin Cook with complete ACL tear
After signing a deal that made him the NFL's highest paid player earlier this summer, Carr certainly looked the part of an ascendant quarterback through four games this year. "He's running the Oakland Raider offense", Harbaugh said.
What to expect from E.J. Manuel: He is what he is - a former first-round bust. He was off to a strong start to the season when healthy, though, totaling three touchdowns and 163 yards in his first two games combined. This has become a question for any team with an injured quarterback.
As such, Manuel will be under center in a really important Week 5 game against Baltimore this upcoming Sunday at the Coliseum.
There's no time too soon for Carr to return, but there's no obvious soft landing spot for him in October, either. The team initially said its quarterback had back spasms, but that wasn't the case. Of course, the less time he misses, the better.
The fact that second-year quarterback Connor Cook lost out on the top backup job shouldn't be a feather in Manuel's cap - it should be a demerit against Cook. So, there is a chance the Raiders' season will not be lost during Carr's absence.