PHOENIX - Add another injury to an already long list for the Arizona Cardinals.

Safety Tyrann Mathieu will undergo surgery on his fractured left thumb on Wednesday and could be sidelined until the team's regular-season finale.

Mathieu will have a pin inserted in the thumb. The Cardinals said Tuesday that the thumb would need "a couple of weeks" to heal, then Mathieu would play with it in a cast.

Coach Bruce Arians said Monday that, if Mathieu needed surgery, the worst-case scenario would have him out three weeks. That would have him returning for the team's final regular-season game Dec. 28 at San Francisco. If he misses only two weeks, that would put him back on the field for what looks to be a crucial game at home against Seattle on Dec. 21.

Mathieu was injured in Sunday's 29-18 loss at Atlanta. It was the second loss in a row for the Cardinals, whose lead in the NFC West has dwindled to one game over the Seahawks.

It was the latest in a series of injuries that have hit the Cardinals, who are 1-2 since quarterback Carson Palmer went down with a season-ending knee injury.

Arizona is without defensive tackle Darnell Dockett for the season due to a knee injury in training camp. Outside linebacker John Abraham sustained a season-ending concussion in the opener against San Diego. Punter Dave Zastudil is out for the season with a groin injury. Outside linebacker Matt Shaughnessy is just returning from the injured reserve/eligible to return list after missing eight games with a knee injury. Wide receiver Larry Fitzgerald and defensive end Calais Campbell each has missed two games. Fitzgerald could return Sunday against Kansas City.

And inside linebacker Daryl Washington is suspended for the season for violating the NFL's substance-abuse policy.

Mathieu's outstanding rookie season a year ago was cut short by a severe knee injury. He was still recovering in training camp, didn't play in the season opener and played sparingly in the first few games.

Tony Jefferson, a starter much of the season, will get most of Mathieu's playing time at strong safety, with Rashad Johnson remaining at free safety.

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