Aaron Wilson at National Football Post gives us the scope:
Interesting to note that Vinatieri was NOT listed as one of seven players who are NOT traveling with the team to Cincinnati to take on the Bengals for the fourth and final pre-season game for 2009. Bob Sanders, who is still on PUP, will stay in Indy while the Colts close out pre-season.
Having Adam back is a big boost. Hopefully, he'll get some time in against the Bengals, working with rookie punter and FG holder Pat McAfee.
Adam's activation means the Colts must cut another player, and that player is likely kicker Shane Andrus. Andrus has been magnificent in camp and pre-season. If you are reading this and you are NOT a Colts fan (and your favorite team is desperate for a quality kicker), look no further than Shane Andrus. He hasn't missed a kick yet in pre-season, and his kick-offs have been consistently good.
[UPDATE]: Good point made in the comments by reddogfred; players on the PUP do count against the 75 man roster limit. Therefore, the Colts do NOT have to cut anyone as a consequence of activating Vinatieri. And yes, I used this update as another excuse to place the word NOT in CAPS again.