I have absolutely no problem with him leaving. As said, he's a great player when fit, but he hardly ever is. He can't be relied on and his wages could be used to accommodate a left-back who is going to offer more. A pay as you play deal would of been ideal, but the state we're in anything else would of been a risk.
If this is true, I wish him well, he always seemed like a decent bloke and it's not like he wanted to be out injured. It's important we bring a player to replace him though, one of the reasons Insua had a dip in form was because he's still a player learning his trade and was having to play every game.