"I've been thinking about it," Wilfork said. "I'm not saying I will do it, and I'm not saying that I won't do it. But it's definitely not off the table.
"One thing I know is that I love this game. One of the hardest pills to swallow [is] to leave something that you love. It's tough. It's got to be tough. Because [it's not like] I'm not walking out banged out or I don't have nothing left in the tank."
Wilfork, 35, said he won't be making the decision until after the season, and that the possibility stems from having other things he wants to do in life.
"There's so many other things that I want to do," Wilfork said. "A lot of interests that I have outside of football, and I'm not getting any younger.
"I love horses, I love to fish. I love to have my own time. I don't like to be on a schedule," Wilfork said with a laugh.
When O'Brien was asked about the possibility of Wilfork retiring, he said he was caught off guard because he didn't know Wilfork was considering it, but that he has had "tremendous respect for him from the time [he] met him in New England."
"I think about two things with Vince," O'Brien said. "I think about his off-the-field, his family, his wife and kids and all the things that he does for the community and Boston and New England and then obviously here in Houston. And then I think about Vince on the field.
"To play nose tackle in this game at such a high level for that many years to me it's incredible. Those positions, there is physical, violent contact on every play. It's not playing farther away from the ball. You're right over the ball. And to be in that position, get double-teamed quite a bit, and to have the productive career that he's had, it's a testament to him, it's a testament to his toughness. He's a good teammate, been a good leader here, and I know this about Vince, he wants to play really well in the playoffs."