UPDATE: A concussion has been confirmed for Welker and he will not return.
Welker was injured late in the second quarter as the Broncos were driving for a late field goal. Welker took a hard shot to the head while unsuccesfully attempting to haul in a pass. The hit was legal and did not draw a penalty flag from the officials.
Welker, who makes a living catching tough passes over the middle from his slot position, has battled concussion issues throughout his career. The last instance was on Nov. 17 against the Kansas City Chiefs. That injury did not cost him any time, though he caught only four passes the following week in his return to New England.
The veteran wideout had five receptions for 61 yards and a touchdown before exiting on Sunday.
After falling behind 21-10, Peyton Manning has led the Broncos back within 21-20 at halftime.