"It's difficult to leave, but I appreciate [O'Brien] letting me do this," he said. "I've got two grandkids in Denver I can see. I had a great experience with the Texans, working with Gary [Kubiak] and [O'Brien] this season. I'm excited to work with Gary again."

While it's nice that Kollar will get to spend more time with his grandchildren, this leaves our favorite team short a defensive line coach and our All-Galaxy DE J.J. Watt bereft of the guy who's coached him since he came into the league. While it's easy to expect J.J. to continue being J.J., the other men along the DL may be impacted by the change, for better or worse.

In his time here in Houston, Kollar worked with some Texans' favorites, like Ninja and Watt, some guys Texans fans learned to appreciate, like Grease and Jared Crick, and some guys we have never come around to, either due to injury (here's looking at you, Nix, and your non-existent knees) or a tendency to disappear during the season, like EMFM.

According to Watt, when asked by OB about Kollar before the Purge, Watt went to bat for his position coach. Kollar was one of two coaches to survive the Battle Red Wedding last January, along with Liga-who-what (who owes everything--and I mean everything--to Randy Bullock and Shane Lechler).

Either way, we're now in the market for a new DL coach, along with the Jets, 49ers, and Raiders (the Patriots don't employ a DL coach, but they may not be looking for one).

Current Falcons' DL coach Bryan Cox might become available, should the Falcons ever get around to hiring a head coach. Many fans first got to know Cox due to "Hard Knocks," and it's hard to argue that he wasn't memorable. While the Falcons disappointed along their DL in 2014, they disappointed all over the field, in the front office, and everywhere else they went, too, so it's hard to get a sense of how much of that defensive failure was on Cox versus how much was a matter of organizational rot that needed to be eradicated. Cox also served as assistant DL coach for the Jets from 2006-08, DL coach for the Browns (2009-10), pass rush coach for the Dolphins in 2011, and defensive front seven coach for Buccaneers (2012-13). The three-time All-Pro LB won a Super Bowl with the Patriots before retiring after the 2002 season.

Of course, Romeo Crennel may decide that he doesn't need a DL coach, since he got his start as the DL coach for Western Kentucky from 1970-74 and again served as DL coach for Georgia Tech in 1980 and the Giants, Patriots, and Jets from 1990 through 1999.

Should the Texans decide a DL coach is a necessity, I can't think of many coaches either in the league or in college who would shy away from the chance to coach J.J. Watt, so we should be okay with finding someone soon enough.

If you've got any realistic ideas about who Bill O'Brien should be chasing to replace Bill Kollar, take to the Comments and share.