They simply were not going to pay his $8.5 million salary.
There have also been rumblings that Bulger could retire. That option becomes more financially viable now that Bulger has been released. Retiring while still under contract could have allowed the Rams to recoup a portion of bonus money paid to him.
If Bulger wants to continue playing, he'll be entering a quarterback market that has largely been settled. I thought the Cardinals might make sense as a possible destination, but they've signed Derek Anderson and committed to Matt Leinart as the starter heading into camp.
The 49ers and Seahawks have also added backup quarterbacks.
Chicago could make some sense for Bulger if he wanted to continue his career as a backup. Former Rams coach Mike Martz is running the offense there. But with Jay Cutler signed for the long term, Chicago wouldn't give Bulger a chance to work his way into the lineup.
Note: Bernie Miklasz says the Rams held onto Bulger in case the Redskins wanted him as part of a trade into the No. 1 overall spot, but the Donovan McNabb deal ended any possibility. Meanwhile, Facebook friend Brendan notes that Bulger turns 33 Monday.