Ryan Dempster, Shaun Marcum, Johan Santana, and Cole Hamels' trade value

Cole Hamels is scheduled to become a free agent at the end of the season. (David Maialetti/Staff Photographer)

I've written several times that I can't see the Phillies trading away Cole Hamels, but that doesn't mean they won't trade him, which does mean we have to keep an eye on the potential market for him. Last week, we broke down what the Phillies should be in a position to demand in return from the star left-hander, who is scheduled to become a free agent at the end of the season. Of course, a lot depends on the market, specifically what other options there are for teams who are looking to upgrade their rotation for the stretch run. In that light, a few recent developments would seem to bolster Hamels' current market worth. Yesterday, the Brewers scratched starter Shaun Marcum from a start due to soreness in his right elbow, the latest health concern for the starter. Marcum, who is 5-3 with a 3.39 ERA, has the potential to be on the market given the Brewers' struggles this season.

 --More significant is the Cubs' decision to place righty Ryan Dempster on the disabled list because of tightness in his lat. A free agent after the season, Dempster has had an outstanding campaign thus far. According to the Chicago Sun Times, there is no timetable for his return, but the injury definitely raises questions about his availability at the trade deadline.

--For most of the first two months of the season, I thought Johan Santana had a shot at becoming 2012's version of 2010 Roy Oswalt, a renowned pitcher with a year-and-a-half left on his contract who emerged as one of the top guns for hire on the trade market. This is a guy who pitched a four-hit complete game shutout with seven strikeouts on 96 pitches six days BEFORE he pitched a no-hitter.

But Santana still has to prove he has rebounded from his 134-pitch effort in that no-no on June 8th. In two starts since, he has allowed 10 runs on 13 hits with 11 strikeouts and five walks in 10 innings. There are other factors that could limit his return -- he has pitched on normal rest in only four of his 13 starts, and has pitched on six days rest twice. Most significant, though, is the roughly $40 million that any team who trades for him will owe him through next season. Oh, and he has a no-trade clause.