Jared Allen and Kevin Williams have established a tears-free period. They've even put a wager on it.

"The first person who cries gets a gut punch," Williams said with a laugh.

The two longtime defensive linemen both could be playing their final game for the Vikings on Sunday against Detroit in the last game at the Metrodome. Both will become free agents after the season.

Any tears before the game will be frowned upon by the two. After the game, though, it will be a different story.

"I joked with him, I don't want anybody crying around here on Friday or Saturday," Allen said. "But we'll enjoy it when the time is right. After the game, that's the time to get sentimental."

There should be plenty to well up about. The two are best friends and are in their seventh seasons as teammates. Since they got together in 2008, Allen has made four Pro Bowls and Williams three.

Overall, Williams, drafted by Minnesota in 2003, has six career Pro Bowl appearances and Allen, who played with Kansas City from 2004-07, has five. They've had some of their best seasons alongside each other.

Allen, a defensive end, has been regarded as one of the NFL's premier pass rushers. Williams, a defensive tackle, has been a rugged run stopper who also has been able to throw some terror into opposing quarterbacks. Many regard Allen and Williams as one of the best defensive line combinations in recent NFL history.