Coleman is a 25-year old who has intercepted seven passes for the Eagles since being a 7th round pick in 2010.
Coleman started a total of 27 games at both free and strong safety in 2011 and 2012, but mostly struggled. He was relegated to backup duties last year and barely saw any time on defense. This Eagles blog post describes him as follows:
Coleman has starting experience and is a solid special teams contributor. But he isn't an adequate back-up and someone you could rely on to step up if someone goes down.
Jets fans might remember Coleman forcing a crucial fumble by Santonio Holmes, which was returned for a touchdown early in the Jets 2011 loss in Philadelphia. That set the table for the Eagles' blow-out win as the Jets, who entered the game 8-5, spiraled into a late-season collapse and missed the postseason. As a rookie, Coleman didn't look likely to make the Eagles roster until he returned two fumbles for touchdowns in the 2010 Bollinger Bowl. He would go on to play in 15 games that season, starting two.
If the Jets made this move, it wouldn't likely carry much (if any) guaranteed money, so his place on the roster would not necessarily be secure. However, it's always sensible to address your special teams units and get some experienced players involved in the competition. The Eagles operate out of an unconventional system, although the Jets do already have Jaiquawn Jarrett on the team who has made that transition.