United may have offered him another one-year extension to continue his playing career anyway but, if not, Pulis would have jumped at the opportunity to sign the former England midfielder.
"If he'd been available, there's no question I'd have been interested in taking him," he told The Sentinel.
"I think there would have been quite a few of us in the Premier League wanting to take someone of his experience and quality.
"So from that point of view it's a shame he's decided to retire now because I'm sure there was plenty of fuel left in the tank.
"But no-one knows that decision better than the player himself and so you have to respect it."