It appears the concerns about Derek Carr’s back injury were a bit understated.

A day after the Oakland Raiders quarterback left a game against the Denver Broncos with what the team called back spasms, Carr has been diagnosed with a fracture and is expected to miss two to six weeks.

Carr’s injury occurred late in the third quarter when he took a hit to his back while unsuccessfully trying to avoid a sack.

After winning their first two games then dropping to 2-2, this couldn’t be worse news for a Raiders team that entered the season with Super Bowl aspirations. Following a 27-10 prime-time loss to the Washington Redskins in Week 3, the Raiders dropped a 16-10 division game to Denver and will now be without their franchise quarterback for about a month.

EJ Manuel, who played admirably while attempting a comeback against the Broncos (11-for-17, 106 yards and one interception) but doesn’t compare to the arm strength and on-field reliability as Carr, will take over the offense. The depth chart gets dicier after Manuel. Third-string quarterback Connor Cook has appeared in only two games and has a career 83.4 rating.

The Raiders are, unfortunately, getting used to playing without Carr. After playing in all 16 games during his first two years in the league, Carr has been sidelined with serious injuries in back-to-back seasons. Last year he broke his leg in Week 16, forcing Oakland to turn to Cook for the season finale and an eventual playoff loss to the Houston Texans.

Still, Oakland had seen enough of Carr to sign him to a five-year, $125 million contract over the offseason. The 26-year-old has already tallied 11,947 yards and 88 touchdowns for his career.

Over the next five weeks, the Raiders will face the Ravens, Chargers, Chiefs, Bills and Dolphins. If Carr can make it back after that he’ll have a bye week to prepare for the Patriots in Week 11.

Oakland was already without wideout Michael Crabtree against Denver as he recovered from a chest injury. What looked like a powerhouse offense coming into the year is going to need to fight through October and get healthy before it can reclaim that title.

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Blake Schuster is a writer for Shutdown Corner on Yahoo Sports. Have a tip? Email him at blakeschuster@yahoo.com or follow him on Twitter! Follow @Schustee