I'd like to see a breakdown on how often he stayed in and blocked as opposed to the first two games. 3-37 on 4 targets is mildly concerning even with a TD.
I think Cameron is clearly ahead of him in the rankings going forward.
Week 1 - played 74 out of 74 snaps, ran routes on 27 plays (targeted on 7), blocked on 47 plays (26 runs, 21 passes)
Week 2 - played 76 out of 76 snaps, ran routes on 34 plays (targeted on 9), blocked on 45 plays (31 runs, 14 passes)
Week 3 - played 77 out of 79 snaps, ran routes on 31 plays (targeted on 4), blocked on 46 plays (39 runs, 7 passes)
The low targets was just variance. Thomas wasn't kept in to block more because of Clady's injury. In fact, I believe on 2/3s of Denver's offensive plays in the first half, there was no TE on Clark's side of the formation. Clark is no Clady, but Denver trusted him on an island. The main adjustment they made was emphasizing the short passing game- Peyton's 2.12 seconds to throw was the lowest in the league last week. Although a lot of that was just taking what Oakland's defense gave them, too, because Oakland spent the majority of the game showing a 6-man box, just daring Denver to run the ball or check it down (which also explains why Denver averaged around 6 yards per carry rushing).
Denver ran some 3-TE sets to open the second half, but that wasn't really about covering for Clark- they'd used the formation last week against the Giants before Clady got hurt, too. I've heard some speculation that, since they were up big, Denver was just using the opportunity to get some extra stuff on film for opposing defenses to prepare for. They wound up splitting Tamme, Thomas, and the RB (Moreno?) out wide and using the 3-TE set as a primarily passing formation against Oakland.
Thomas's target total in week 3 was just random variation.