I've never been an enormous fan of Delonte West's. I don't think he's a starter in the NBA on a championship team. That said, I'd take him back if Posey walks. He doesn't fill Posey's shoes, but he makes it a bit easier to do so. He'd be an upgrade over House as the backup PG; moreover, he'd provide better scoring than Posey backing up Ray Allen. If he could backup the 1 and 2 spots, that'd mean a guy like Giddens would only have to worry about backing up Pierce for 10-12 minutes per game, which is realistic for a guy like him.
I don't see it happening, but I like him as a midlevel replacement for Posey better than most options.