The price has to be right, of course, but I think in the following cases many of these players are likely to be available at a discount to their draft-day prices.
Justin Verlander - his stuff is as good as ever, and while the command has been spotty, he's been unlucky with BABIP. Justin Upton - he's been in and out of the lineup and has hit seventh or eighth most games, but expect the talent to shine through eventually. He's also been drawing walks which means he's not as lost as his other numbers would suggest. Clay Buchholz - Justin Masterson pitched well in place of Daisuke Matsuzaka, but I'm not sold on Brad Penny, and Buchholz should have a significant role to play this season. Jarrod Saltalamacchia - he's off to a slow start, but he's a good prospect in a great spot. There's still a lot of upside here. Jimmy Rollins - savvy owners realize they're married to the guy, but if anyone's getting impatient, go ahead and offer Aaron Hill, Paul Maholm and a throw-in and see what happens. Ricky Nolasco - he's pitching fine but is a strand rate and BABIP casualty. Should turn it around. Kevin Gregg - he's still the Cubs closer, even though everyone seems to think it's only a matter of time before Carlos Marmol wins the job. (I'd trade Marmol straight up for Gregg any day as Lou Piniella likes the current arrangement, and only an implosion from Gregg will change that). Jason Motte - I wouldn't give up a lot for him, as Ryan Franklin has done fine so far as the team's closer. But the Cardinals picked Motte out of spring training for a reason, and if Motte continues to settle down, he's likely to get the next shot at closing if and when Franklin fades.