DeShaun Foster is assumed to be playing second fiddle to DeAngelo Williams this season, hence nobody wants to draft him. That said, I look at him as a value pick in the later rounds; I can see him being a reasonably good RB3 for you, which is a great bargain in the 'teen rounds. Also, he has injury concerns.
Steve McNair... well, he's old and he's throwing the ball in Baltimore. That said, I don't know why he's going as low as he does. He should improve his numbers in his second year in the Baltimore offense, and the Ravens have several WRs poised for breakouts.