Apparently the Minnesota Vikings had a different idea about how to fill their quarterback depth chart than I did.
Rosenfels was with the New York Giants during the pre-season, but spent most of the pre-season hospitalized with complications from strep throat. He was released by the Giants in October, and then signed by the Dolphins after they lost starter Chad Henne for the season. He became ill again after signing with Miami as well, and was on Miami's reserve/non-football injury list before being waived on Thursday.
So, we have a veteran to back up Christian Ponder now. I'm not really surprised that they decided to go the direction of a veteran rather than another developmental guy, but I guess they decided they needed a veteran who was content to be a backup rather than someone that thought they were still going to be a starting quarterback.
Welcome back to Minnesota, Sage Rosenfels.
EDIT: Apparently, according to the Atlanta Journal-Constitution, the Vikings DID attempt to sign a quarterback off of a team's practice squad. Only, instead of Denver's Adam Weber, it was Atlanta's John Parker Wilson.
Not sure if they would have gone with Rosenfels had they been successful, but it stands to reason that they would not have.
EDIT to the EDIT: Also, (not) surprisingly, nobody claimed Donovan McNabb off of waivers, so the Vikings will owe him the balance of his salary, a shade less than $1.5 million.