Welker sustained a concussion in Denver's preseason game against the Houston Texans on Aug. 23, his third in the last nine months after he sustained two in a three-week span late last season.
The receiver was then suspended for the first four games of the season early this month for violating the league's substance abuse policy. But Welker is one of several players who will reportedly have their suspensions lifted under the terms of the new drug agreement, since Welker wouldn't have violated the terms of the new policy.
The NFLPA is scheduled to vote on the new drug agreement Friday afternoon.
According to Klis, Welker may not be made active by the Broncos even if allowed to play Sunday.
Welker, 33, had 73 catches for 778 yards and 10 touchdowns in his first year with Denver last season. The Broncos host the Kansas City Chiefs in Week 2.
- Ben Estes