UPDATE (7-23-05): As of the 2005 NHL collective bargaining agreement (or CBA) following the lockout that wiped out the 2004-05 NHL season, the waiverdraft appears to have been eliminated. This means the NHL waiverdraft is now a dead relic of the past. This appears to have come about because the new CBA will let players become Unrestricted Free Agents (or UFA) at the age of 27 now, whereas under the old CBA players had to wait until the age of 31 before the could become a UFA. With players becoming UFA's at a much younger age, the need of a draft to disperse talent throughout the league has greatly lessened.
The NHL Waiver Draft (sometimes called the "Waiverdraft") is held once a year at the end of the exhibition season and before the regular season gets underway. The idea behind the waiver draft is to ensure some sort of spread of talent throughout the league. In other words, to prevent powerhouse clubs from hoarding talent they maybe aren't using that some other franchise could honestly use.
The waiver draft is also a tool often used by teams to try and dump a player who is making a large salary and for whatever reason may no longer have a place with that team.
For example, in the 2001 Waiver Draft the Detroit Red Wings didn't protect goalie Chris Osgood because of their recent acquisition of goalie Dominik Hasek from the Buffalo Sabres. With Hasek taking over the starting job, Osgood no longer had a place fitting his high salary, and since the Red Wings couldn't trade Osgood they chose to expose him to the waiver draft. Osgood was subsequently claimed by the New York Islanders, who were needing some experience in goal. Most people would agree that both the Red Wings and the Islanders accomplished good things for their organization in this transaction, as a result.
The waiver draft bears more in common with an expansion or dispersal draft than an actual amateur draft, and key differences should be noted (especially the Exemptions, which will be touched upon later on).
The following were the rules and stipulations used in the 2001 NHL Waiver Draft:
* Each team can protect a list of 18 Skaters (Centers, Wingers, and Defensemen) and 2 Goalies on its active roster (including minor-leaguers). These lists are then published and released throughout the league for all to see and look over.
* Teams pick in reverse-order-of-finish of the previous season (essentially the same as the Amateur Draft). In other words, the team that finished with the worst record the previous season gets the first overall pick.
* In the first round of the draft, only teams that failed to make the previous season's playoffs may participate in claiming. Teams can also not claim from other teams in their own division in the first round.
* No team can lose more than three players in the draft unless a team specifically chooses to offer more than three. This limit increases with each claim made from another team during the course of the draft. (IE: If another team claims one of my players and yet I claim another team's player, I still can lose up to three players total).
* No team that lost a goalie in the 2000 Expansion Draft may lose a goalie in the Waiver Draft unless said team specifically chooses to do so.
* The draft is complete when a round occurs in which no teams make picks or claims.
Not all players are eligible to be claimed, even if left unprotected. The NHL uses a complicated table using criteria such as age and "NHL Games Played" to ensure that young prospects can't be claimed. I won't delve into the exact formula here because of its complexity, but suffice to say that an 18-year-old prospect would have to have played a lot of NHL games before he'd lose his exemption.
Overall the waiver draft does a commendable job of "levelling the playing field", as it were. Powerhouse franchises such as the Colorado Avalanche, Detroit, New Jersey Devils, and Philadelphia Flyers are kept from hoarding talent they don't need, and lesser clubs like the Minnesota Wild, Tampa Bay Lightning, and Atlanta Thrashers are able to use these players to fill holes in their roster to remain competitive.