2. The Blue Jays have a wealth of prospects in their system. With the Cubs still apparently looking to build for the future, some of these pieces could be more valuable to the Cubs than Matt Garza who's contract is up after 2013.
3. With Drabek out for a while, Garza can essentially replace him in the rotation, adding more experience and reliability.
4. With the packed AL East, I don't think it would be wise for the Blue Jays to risk trading prospects for a player who is under contract only until the end of this year, while still having only an outside chance to make the playoffs anyway. If the Blue Jays make a trade, it has to be someone who is under contract for more than one year, like Garza rather than say Greinke, Hamels, etc.
I don't see any other team being a better fit for Garza than the Toronto Blue Jays. Acquiring them Garza will make them a better team for not only this year but for next year as well. I could see a trade looking something like this:
Garza for Kyle Drabek, Aaron Sanchez, and Chad Jenkins.