Because Pujols is due a huge payday after next year I believe. If they want to keep payroll reasonably close to where it is, they can't afford $15MM for Holliday, $18 MM for Pujols, $10MM for Carpenter and Lohse, an ever increasing price tag for Wainwright and keep a decent roster elsewhere. If he continues on his hot streak, I'm pretty sure he walks. They can probably keep DeRo, but even with the money they have coming off the books this year (Pineiro, Glaus, Green, etc.) they'll have a bunch of holes to fill and not a ton of money or ML ready prospect to fill them.