Polamalu is obviously not the same player he was just a few seasons ago, but the Giants wouldn't ask too much of him. He could be a situational player that adds depth and experience to a very green group of safeties.
But the questions that would need to be answered before such a move was to be made would start with Polamalu's health and how much desire he has to continue his career in a new venue. From Rotoworld:
Polamalu said he made the decision (to retire) so he could spend more time with his family. The Steelers asked Polamalu to retire months ago to avoid the awkwardness of cutting him. The 33-year-old was a remarkable talent, appearing in eight Pro Bowls during his 12-year stay in Pittsburgh. Polamalu won two Super Bowls and was named 2010 NFL Defensive Player of the Year. Injuries marred the end of his career, but there's no doubt Polamalu is Canton bound. He was the rare (only?) safety around which a defense was built; Dick LeBeau specifically designed his defense to allow for Polamalu's highly-disruptive freelancing.He may not be a fit for what returning DC Steve Spagnuolo is planning to do with the defense, but then again, in the right context he may be. Now, how healthy is he?
The consensus is that Polamalu has lost more than a step and can no longer play with the velocity or voracity he did in 2013, when he played in all 16 games. Last season, he was dogged by a knee injury that kept him out of four games and rendered him ineffective for most of the season.
I say the Giants pass. That is, if Polamalu is available. He may stay retired. He'll be 34 this month and is well out of the club's "young and cheap" free agency policy. Plus the Giants don't have the appetite for oft-injured players. They have enough of their own.