Reading the comments, there appears to be some confusion on the new short-term Injured Reserve designation. Here is the section of the NFL bylaws pertaining to the rule.
Since this rule is being adopted after the cutdown to 75 players, for 2012 only, the NFL and NFLPA have agreed to a transition procedure that permits clubs to return to their 53-player active list one player placed on Reserve/Injured since the start of preseason training camp. This selection of that player must be made no later than 9 p.m. ET tomorrow [today], Friday, August 31.
Following the cutdown to 53 players, the new Reserve/Injured rule will work as follows:
1. Only players with a "major injury" who are placed on Reserve/Injured after 4 p.m., New York time, on Tuesday, September 4, or thereafter during the season, will be eligible to be reactivated at a later time.
2. A "major injury" is defined as an injury that renders the player unable to practice or play football for at least six weeks (42 calendar days) from the date of injury.
3. Each team may reactivate only one player placed on Reserve/Injured after 4 p.m., New York time, on Tuesday, September 4. That player must be "designated for return" at the time the club places him on Reserve/Injured, and such designation shall appear on that day's Personnel Notice.
4. Such player is eligible to return to practice if he has been on Reserve/Injured for at least six weeks from the date he is placed on Reserve. He is eligible to return to the Active List if he has been on Reserve/Injured for at least eight weeks from the date he is placed on Reserve.
Neither Shaun Rogers nor Terrell Thomas were "designated for return."
The way this is explained to me the Giants could still use this rule on someone like Marvin Austin or Will Beatty, beginning Tuesday at 4 p.m. Or, using the "September 4, or thereafter during the season" portion could place someone on IR in-season and return him to the roster after the appropriate amount of time (thanks to Ralph Vacchiano of the Daily News for making me actually use my reading glasses).