The Giants placed Sweeney (undisclosed) on the reserve/non-football illness list Tuesday, per the NFL's transaction log.
Sweeney is set to miss at least the first four games of the regular season, as a result. The depth tight end suffered an undisclosed medical emergency Aug. 23, but coach Brian Daboll said, "he's good" after the event. It remains to be seen when/if New York expects to have Sweeney back on the field this season.