The discussions about why defensive tackle Earl Mitchell wasn't a great fit for Romeo Crennel's Houston defense were made through comparisons.

Mostly a comparison to one player: Patriots nose tackle Vince Wilfork.

He didn't play for Crennel long, just in his rookie year, but Wilfork fits the mold perfectly. He's a massive human being. A massive, but explosive two-gap nose tackle. Mitchell, who left Houston for the Dolphins in free agency, has a valuable skill set, but it's one that will serve him a lot better in Miami.

(An aside: It was Wilfork's Achilles injury that made room for Chris Jones, the Texans draft pick who eventually wound up with the New England Patriots, to get as much playing time as he did. Jones played the most snaps of any drafted rookie on the Patriots' roster last season -- though it wasn't with the team that drafted him.)

Wilfork asked the Patriots to release him today, according to Ian Rapoport of NFL Network. That this request comes some time after the Patriots reportedly asked Wilfork to take a pay cut and one day after the Patriots made cornerback Darrelle Revis their highest paid defensive player.

If the Patriots acquiesce (and why wouldn't they?) Wilfork becomes an excellent option for the Texans, even at 32, provided his injury doesn't hinder him. The Texans, of course, have a tortured recent history with trusting the health of a very talented veteran. But you'd imagine the Ed Reed fiasco would make them even more thorough in their decision with a guy like Wilfork.

As the hours ticked off in this league year, some of the prime suspects to fill out the Texans' roster went off the market. It left me poring free-agent lists for the biggest nose tackles out there, whose talent and size would be helpful to the Texans.

Wilfork's addition to that dwindling list is good for Houston. Another player still on the market is former Packers tackle B.J. Raji, another large man (6-foot-3, 337 pounds) who could be a better fit in Houston than he was in Green Bay recently. Last season was Raji's worst, but back in a block-eating, nose-tackle role, he could be very effective.

The Texans will add nose tackles because they have none at the moment. They don't have to solve all of that problem in free agency, but it could be a start. The options aren't many to begin with and get fewer with time.