Yeah, an IR position is a must. I agree that 2 is probably a good number.

Also something to consider, whomever is picked to set this up....try to schedule the draft as close as you can to the opening season start date (Oct 5th). That way if anyone is injured during the mini-camps or pre-season games, people won't pick them. I've been in some leagues that drafted a few weeks before the season opener, only to see my first round pick blow out his knee one week before the season even started.