I agree completely. This is my reasoning, as well.
I completely understand the counterpoint. Shake the rust off, try to win the next two games, yada yada yada...
However, this is the first chance in A.J.'s nine years as a Texan that he has the opportunity to play in the postseason.
He's not playing against Indy. So, if I was a coach, I'd let the chips fall where they may this weekend and see the results of the Steelers, Ravens, and Patriots games. It might not even be possible to grab a first week bye, and if that turns out to be the case, the outcome of the Titans game could have no impact on playoff seeding order. In that scenario, it's a no-brainer to rest A.J. for the playoffs.
The catch will be if the Titans game is a 'must win' to earn that first round bye. Then the team has a really tough decision to face, because that's a huge advantage for teams in the playoffs.