The defensive tackle is active and made an immediate impact, blocking a Neil Rackers extra-point attempt following a Texans' touchdown on their opening drive.
"The reality, we lost Gerald for the season, we're 4-4 and still in the thick of it, we've lost our last two and we're one game off the wild card," Dominik said. "We don't think we're out of it."
The Bucs were the only team to put in a waiver claim on the former All-Pro, assuming the $706,000 left in base salary. The incentive clauses, too, will apply going forward.
Haynesworth played 25.2 percent of the Patriots' 531 defensive snaps. He has a $1 million incentive if he plays 20 percent of the snaps, and $590,000 markers at 45, 50, 55, 60 and 65 percent.
The Associated Press contributed to this report.