The buzz around the net is that the top five pitchers in current trade discussions are:
1. Jason Hammel, Cubs.
2. David Price, Rays.
3. Cliff Lee, Phils.
4. Jeff Samardzija, Cubs.
5. Dellin Betances, Yankees.
Hammel was always a sign and flip guy. This has been the Cubs operating procedure for years. Since Hammel is a pure rental (a free agent at the end of the year), the Cubs hope to make a deal like Scott Feldman to the Orioles last year (which netted a fallen Jake Arrieta).
Price had a great 2012 campaign (20-5, 2.56 ERA). He is still under contract for 1.5 seasons so an acquiring club has a staff ace for two pennant runs. That is why the Rays asking price on Price will be so high. But since the Rays have tumbled this season (and currently are in the position to take the #1 pick in 2015 draft), there are a few observers who think it may be better for the Rays to keep Price through 2016 and draft his replacement in June.
Lee was a quality veteran, but he sustained an elbow injury in May. The problem with Lee is that he is old and expensive: he is owed $25 million in 2015 and $27 million in 2016. No team is willing to take such a payroll hit on pitcher with current injury issues.
Samardzija has been discussed at length on this site. Like Price, Samardzija has 1.5 years of control left so a team can have him for two pennant drives. However, in comparison to Price, there is no comparison. Price is a #1 starter; Samardzija would be a #4. The Cubs are trying to trade Samardzija as a #1 guy (in order to get four top prospects) so the Cubs may be overplaying their hand to a point where they can't trade him.
Betances is an interesting name that popped up in GM circles. He is currently the Yankees 8th inning set up man. He has been lights out. His record: 4-0, 1.51 ERA, 70 K with a strikeout rate of 15.1/9 IP. Teams looking for bullpen help are asking about Betances, but the Yankees would be dumb to move such a valuable piece. The Yanks are in the market for a starting pitcher, but old GMs had a saying that you don't trade a quality starting pitcher for a reliever.
Of all the top pitchers making the trade market rounds, Price is clearly the top name on the board but Hammel is the most likely to get dealt.