Do the Cowboys need to draft a DT?

One of the questions in today's chat raised an under-discussed aspect of the Dallas Cowboys' issues in advance of next Thursday's NFL draft:

Don (Indiana): Hey, the Cowboys need offensive linemen. This shouldn't be news. They will try to get one in the first couple rounds. Still not news. I am concerned with what they do at the 1. Clearly [Josh] Brent is out and [Jay] Ratliff has shown durability issues recently. I think that this position may be more important to address right now than safety, what do you think.

Dan Graziano: I think I agree with you. The conventional wisdom says the Cowboys need a playmaking safety because they haven't had one in so long. And that may be so. But I think you're right that the line might be the more pressing need.

Our man Calvin Watkins delves deeper and more specifically into this idea in a post for ESPNDallas.com, in which he wonders whether the Cowboys might look to draft a defensive tackle in the first round. Calvin notes that Mel Kiper Jr. is projecting the Cowboys to take North Carolina defensive tackle Sylvester Williams with the 18th pick (in a first round in which he projects the elite offensive line prospects to be long gone by then), and thinks it could make some sense given the issues surrounding projected starters Jason Hatcher (entering the final year of his contract) and Jay Ratliff at the position:

Ratliff's status becomes sketchy if the team drafts a defensive tackle who is able to push the pocket. His spat with owner/general manager Jerry Jones, his declining play -- attributed to double-teams -- and his DWI arrest, doesn't give him much cushion with the front office. While the coaching staff values Ratliff, he played only six games in 2012 and it has to be frustrating to deal with his mood swings.

When healthy, Ratliff can be a dominant force. The Cowboys need to keep him on the roster because they know what he means to the defense as a whole. But that doesn't mean the Cowboys can't draft a defensive tackle for more depth or to replace Ratliff or Hatcher in the future.

The question, which Calvin proceeds to pose, is whether Williams or the other defensive tackles who might be available at that spot are worthy of such a high pick. Williams is a well-regarded older prospect who will turn 25 during his rookie season and whose pass-rush skills need developing. He could be a guy who could contribute right away and also develop into a starter for when they need one down the road. But is he the kind of elite-level prospect who merits a first-round pick over a playmaking safety like Kenny Vaccaro?

Personally, I think the Cowboys need to take an offensive lineman at 18. I think there are six who would be good picks, and the last time six offensive linemen went in the first 17 picks was 1966, when the league only had 15 teams. So I think an offensive lineman will be there and that they should take him. But if something weird happens and that's no longer a possibility for them, don't be surprised if they look to the "other" line to find their first-rounder.