Vikings RB Mason placed on IR after having surgery on thumb

EAGAN, Minn. -- Minnesota Vikings running back Jordan Mason will miss at least the next four weeks after undergoing surgery to repair a fractured thumb, coach Kevin O'Connell said Wednesday -- a second significant injury for the team's offense one game into the season. With quarterback Kyler Murray's status in doubt for Sunday's game at the Chicago Bears as he works through the concussion protocol, the Vikings scrambled to find depth behind starting tailback Aaron Jones Sr. They promoted veteran back DeeJay Dallas from the practice squad and signed another veteran, Jerome Ford, to the practice squad. The team also has rookie running back Demond Claiborne on its roster, but he was inactive for the Vikings' 39-22 victory over the Green Bay Packers in Week 1. Although Jones got the start Sunday against the Packers, Mason led the team with 15 carries for 59 yards. It is unclear when he suffered the injury, but O'Connell said Mason reported soreness Monday, leading to further examination. O'Connell said he did not anticipate Mason's recovery taking longer than four weeks. The likeliest scenario is that Dallas, who signed with the Vikings on Sept. 2 and played seven snaps against the Packers, will be the primary backup Sunday behind Jones. Dallas, who was in training camp this summer with the Jacksonville Jaguars, has carried 22 times over the past three seasons while playing for the Seattle Seahawks, Arizona Cardinals, Carolina Panthers and Jaguars. "He's a very, very smart player," O'Connell said. "The physicality that he plays with on [special] teams shows up in pass pro, and he's got some good instincts and vision and tools as a runner. So to have him available to us here has been big." Murray, meanwhile, was scheduled to be a limited participant in practice, three days after a concussion on his 11th play Sunday that left him motionless on the field at U.S. Bank Stadium. Multiple teammates confirmed that his body was in the fencing position, a common side effect of concussions. O'Connell said the Vikings will monitor Murray day-by-day and added: "The protocol is kind of the guiding light." Assuming Murray does not play, backup Carson Wentz would start against the Bears. J.J. McCarthy would presumably back him up, and second-year quarterback Max Brosmer could be elevated from the practice squad.