There are players under an existing contract, there are restricted free agents, there are unrestricted free agents. There are players on their entry-level contracts, AHL contracts, NHL contracts, and tryout contracts.
So, yes; there is a lot of information to consider when putting together an AHL roster for the season. We’ve compiled some information to help make the summer a little easier to understand.
The following article is a re-post from Utica Comets homepage which I found very useful to myself and I think it'll be useful for you too.
That being said, there IS a limit that a team can only dress 18 skaters and two goalies in each game, so it doesn’t make practical sense to carry much more than 23 healthy bodies on a roster.
The NHL also has a limit on 50 standard player contracts (SPC) per season. This is usually not something that comes into play since most teams keep a few contracts in their back pocket. The 50 contracts cover the entire NHL roster and the majority of their AHL affiliate, plus teams may need to hand a couple out at the end of the season to top-end free agents out of college (example: Mike Zalewski was signed out of R.P.I. by the Canucks in late March and counts as one of the 50 for the 2013-14 season).
NHL vs. AHL - the majority of the players in the American Hockey League are actually on NHL contracts. This gives the NHL clubs the ability to send players back and forth between their AHL affiliate and the NHL team. Players on AHL contracts (signed by the Comets and not the Canucks) cannot be called up to the NHL.
For example, during the 2013-14 season Cal O’Reilly was on an AHL contract. If the Canucks wanted to call up O’Reilly, they would have had to sign him to a new NHL contract (one of the 50) before that could happen.
Two-Way vs. One-Way - The difference between one-way contracts and two-way contracts is about money, not about movement. A two-way contract means that players are paid one salary for their time in the NHL (the minimum NHL salary for the 2014-15 season is $550,000) and a much different salary for their time in the AHL (minimum AHL salary for 2014-15 is $42,375). When you hear the term “one-way contract,” it is referring to a player that will be paid his NHL salary even if he is sent down to the AHL. Famously, Wade Redden was sent down by the New York Rangers to Hartford in 2011-12 and was making $6.5 million while playing in the AHL. It prompted the NHL to change the rules to include contracts like that against the NHL salary cap while playing in the AHL but it does not prevent teams from sending players on one-way contracts down to the AHL.
Players on one-way NHL contracts can be sent down (as long as they clear waivers) however players on one-way AHL contracts cannot be called up (as explained above). There are also two-way contracts that work the same way between the AHL and ECHL as they do between the AHL and NHL.
Entry Level Contracts
At face value, a PTO is a contract for 25 games. In reality, a PTO is for as long or short as a team wants it to be. A player can be released from a PTO at any time (even without ever playing in a single game). On the other hand, if a player signs a PTO and plays all 25 games he can simply sign another PTO that allows him to remain with the team. These are not always for players from the lower leagues. Sometimes these are utilized by veterans in order to keep their options open from NHL teams. Last season, Kent Huskins signed multiple PTO’s with the Comets before signing an AHL contract. A veteran of over 700 professional games was unable to secure an NHL contract at the start of the season. He joined the Comets on a PTO in November to play in the AHL without limiting his chances of signing with any NHL team. ATO’s are amateur tryout contracts. These are handed out to players near the end of the season to enable them to play in the AHL without losing their amateur status and enables them to return to the CHL the following season.
Each player’s veteran number is calculated once before the season begins. So if a player finished the 2013-14 season with 260 games played he will not be a VE at all during the 2014-15 season.
Technically there is no limit on how many Veterans or Veteran Exempts a team can carry on their roster. But there are restrictions to how many of them can dress in each game. The limit of combined Veterans and VE’s that can dress in each game is six. At least one of those skaters has to be a VE. So you cannot dress six veterans in a game, but you can dress six VE’s in a game. Veteran rules have no effect on goaltenders.
These six veteran spots are often treated like gold by AHL teams, and they should be. The vets are many of the best players in the league and are often the players you want teaching your prospects as they develop. They are the captains and leaders the spots are not easy to come by. This rule is the reason you see above average AHL players head to Europe to continue their career once they obtain veteran status.
So when a player is drafted, they can either enter the NHL immediately or return to the amateur ranks. They cannot play in the AHL until they are 20 (or about to turn 20). The age restriction does not apply to players signing an ATO. So as you can see, that is a lot to consider when building an NHL / AHL roster. Keep in mind that they are built together. The AHL roster is there to support the NHL club and every piece of the puzzle is calculated to ensure players continue to be developed for the next level.
1 - Constructing an NHL Roster