The most recent defensive players of the year in the NFL top our IDP rankings. J.J. Watt, seemingly healthy, is back in the No. 1 spot. Khalil Mack slips behind him. Depending who you ask and what the eligibility rules are in your particular fantasy league, even that might be way too high.

Watt missed most of last season due to back surgery, but he's healthy now. He's played very sparingly in the preseason -- just 6 snaps against New England last week -- but had a tackle for a loss in there. Looks like he's fine, and when you combine his sack potential with his tackle numbers (two years ago he was No. 1 in sacks and No. 2 among linemen in tackles) he's the clear top IDP on the board.

Mack is a trickier case. As noted in a recent factoid, he has more sacks than any other players over the last two years (26), even while his defense has been a lesser unit in that regard. Regardless, he's a top lineman, as long as your league gives him credit for being a lineman. And some don't.

The Raiders play both 4-3 and 3-4 defensive fronts, with Mack shifting between being a defensive end and outside linebacker. They play enough 3-4 formations that Rotoworld and Myfantasyleague.com now choose to list Mack as a linebacker, where he's not nearly as valuable. Problem is that the team website, NFL.com, and the weekly gamebooks continue to list Mack as a defensive end. And so do we.

I contacted the writer who does Rotoworld's depth charts. He says the Raiders run a majority of 3-4 snaps and Mack is a base OLB. My feeling is, who are we to determine positions? Remember when Jimmy Graham had the whole debate over whether he should be franchised as a wide receiver or a tight end? If the Saints lined up Graham as a wide receiver more often than as a tight end, should fantasy leagues change his position?

We need a uniform determination of player positions -- some go-by that fantasy leagues can rely on. If Raiders.com decides to list Mack as an outside linebacker, so be it. Right now, he's an end.

Subscribers can download an excel file, change Mack's position, and see where he falls in the linebacker rankings. It should also be noted that commissioners of leagues at Myfantasyleague.com can change player positions. We ran into this issue in a league of mine last year; the site listed Bears tight end Daniel Brown as a wide receiver, as he'd been listed with his previous team. So if you believe Mack should be an end, petition your commissioner.

--Andy Richardson