I believe that the unofficial rule (and it is in debate) is that an injured player must show up to get credit for a Pro Bowl appearance - but I don't have a definitive link to prove it.
I do remember the 2006 Pro Bowl roster being very comical at QB for the AFC.
Here's the roster:
2006 Pro Bowl
AFC QB:
Peyton Manning (6) Indianapolis Colts Quarterback
Trent Green (2)# Kansas City Chiefs Quarterback
Steve McNair (3)# Tennessee Titans Quarterback (even funnier is that he was a Raven in 2006, not a Titan)
Players unable to play due to injury:
* Carson Palmer, Cincinnati Bengals Quarterback
* Tom Brady, New England Patriots Quarterback
* Drew Brees#, San Diego Chargers Quarterback (first alternate)
* Jake Plummer#, Denver Broncos Quarterback (second alternate)
So McNair was the 7th QB added for the AFC.
I think that all 7 got credit for a Pro Bowl that year.
Now, as for the debate over credit, I found this about Ray Lewis:
The Sports Economist
Thursday, December 31, 2009
When is a Pro Bowler not a Pro Bowler?
The Baltimore Ravens and the NFL are involved in a dispute over the number of times Ray Lewis was a Pro Bowler. You must be asking yourself, "Is this serious?" Well, I am not joking, but I hardly take the issue as serious.
It seems that a couple of years ago, 2006 I believe, Lewis was voted to the Pro Bowl but was injured and did not go to Honolulu for the game. Instead, he chose to stay home so that the alternate, his friend and teammate Bart Scott, could go. Having been voted to the Pro Bowl, Lewis was paid the incentive money stipulated in his contract by the Ravens. The Ravens also paid Scott the incentive for making the Pro Bowl.
Where the dispute arises is that the NFL does not count that year as a Pro Bowl season for Lewis, while the Ravens do. Why does this matter? If that season is counted as a Pro Bowl season for Lewis, his recent selection this year moves him into second place for the most Pro Bowls by a Linebacker. Not counting it, Lewis is tied with two or three others. More to the point, with it counted, Lewis is one closer to passing Junior Seau for the most Pro Bowls by a linebacker. That seems to be important to some people, and I suppose in a way it is.
The NFL apparently feels that Lewis cannot be recorded as a Pro Bowler for that season because counting it as a Pro Bowl season is one of the incentives to get players to participate in the game. It is important as a marketing tool to get the stars to show up. By not attending, Lewis apparently reduced the luster of the game and opened the door for other stars to not attend but to still be called a Pro Bowl player. That move seems to threaten the NFL's cash flow from the game, which is apparently the whole point of what is otherwise a pointless game.
One further note on this issue. Perhaps the NFL ought to figure a way to have Pro Bowl players actually be those having special seasons. Perhaps players who have missed substantial proportions of the season, like Ed Reed who has missed a quarter of his team's games and Troy Polamalu who has missed (I think) 7 of 15, should not be eligible.
Hope this helps.