Is 21 in durability for a DIII Center too low to take a chance or is it an acceptable risk?

The way the game is now, injuries are fairly rare. They do happen, but as long as you have a deep team to begin with, you're usually fine if a guy goes down for a few games.

Because of that, I don't even consider durability at all during recruiting, especially at D3. Honestly the guy could have a durability rating of 1 with no potential to increase and if he has whatever else I'm looking for, I'm going after him.

Durability is worthless. In my last 10-15 HD seasons (all in the last year), I have had one player get injured and he was out for one game. Ignore it completely.

I have had players get injured for waaaay longer than that and it has made a difference

That said, it is rare and I dont think of DUR as anything more than a tiebreaker or small minus if it is real low.  It should not in my opinion be a meaningful concern in recruiting

Durability is a throw-away rating in my book. It's biggest impact seems to be on the rate of recovery should a player get injured. I took a player with a 1 durability once, he built it up to a 4 by graduation...kid played every game and was a sophomore-senior starter for me. 

Now that I've posted this, I will go make plans for my 95 durability stud to get injured preseason and miss the whole season. 

Durability matters zero.

I look at durability and even search for it...setting of 20 or below...means the other core type attributes are higher.