Per Mike Klis, the team signed McManus to ensure they could activated him "on moment's notice." It's a sensible move for a team that kicks off a hell of a lot more often than it attempts field goals (last week's five-FG game inclusive).
FWIW, Andrew Mason views the re-signing as aimed more toward the 2015 season and possible camp competition for Barth.
On the injury front, Demaryius Thomas was held out of Thursday's practice; he suffered an ankle bruise on Wednesday that leaves him "day-to-day" according to John Fox.
Wideout Cody Latimer suffered an apparent concussion on Thursday, so it would seem likely he'll be inactive on Sunday against Buffalo.
Aqib Talib again practiced fully, while Julius Thomas was again limited.
Denver worked out 11 players on Tuesday; Klis says the tryouts were likely intended for possible 2015 future contracts.