Thats a tough call, I figured I would reply to this being that I have both Welker and Bush on my team as well. I share the same wonder about Moss-less Welker being a good thing or a bad thing. I feel he is still a good play however, and he's in my lineup. Bush coming off a big game, and a big Raider win, would most likely be in for more of the same, and may just be the more reliable play. Go with Bush.
Most weeks I would start Welker, ESPECIALLY in a PPR format -- HOWEVER -- the Pats face one the NFL's best, most physical defenses/pass-rushes in the Ravens, and while New England has had Baltimore's "number" during the regular season in recent years, I believe that the Pats' O-line is ultimately suspect, and I would not count on Brady having much time to throw -- even from the shotgun on sunday -- WHEREAS M.Bush finally got his opportunity to carry the load for OAK last week and performed admirably against a decent San Diego run-defense/defense in general with over 100yds/TD on the ground and like 25-30 more yds in receptions. let's face it, San Fran is currently in a death spiral of sorts at (0-5), with no end in sight, while the Raiders are showing that familiar "swagger" once again and are undoubtedly looking forward to proving which team rules the Bay area this season; OAK has been doing it mostly on the ground in 2010, so while DMC's presence in the lineup this sunday might steal some touches away from Bush (unlike last wk where McFadden got a much-needed rest in an effort to get healthy) DMC won't get anything close to a 50-50 split imo, he will serve as a change-of-pace option to merely SPELL Bush until Darren is closer to 100%, therefore, in my mind Bush will get more touches than Welker overall and may very well catch just as many passes... just my rationale/2c cuz I am starting Bush TOO, but over T.Jones in my non-flex, non-PPR formatted league... GL!