Word from inside the Rams front office is that Rams running back par excellence Marshall Faulk will retire.
Sources also claim that the Rams will be looking for a backup running back on hte free agent market, and would like to find one that can combine with Pro Bowler Steven Jackson to form a 1-2 punch similar to what Fred Taylor and Jones-Drew gave the Jaguars this season. Colts RB Dominic Rhodes is reported to be someone of interest to the Rams; although, he's sure to be a high priced free agent.
Personally, I don't know how much stock I put in the idea of finding a 50% back up running back. The Rams arguably have the best RB in the NFC, and taking him off the field other than to rest him every now and then seems to be self-defeating. Of course, this is just an internet rumor (the Faulk thing has legs though). The Rams need a big, explosive back to power through opposing D-lines in those 3rd and inches situations as much as they'll need the backup to spell Jackson.