In a given year, the amount a player's contract counts towards the salary limit comprises basic salary plus prorated parts of bonus money. Any bonuses awarded for being on a team's roster ("roster bonuses") are fully taxable during the fiscal year in which they are paid. If a player is released before the start of the season, his remaining cap charge is erased. For example, let's say that the Lions have a salary cap of $120 million and they've got $60 million worth of contracts committed to at the beginning of the season. They can't sign any more players without releasing someone else, so they'll need to cut some guys to make room for new players. But after they release someone, their remaining cap space will be $60 million instead of $0 like it was before they signed him. Here's how it works: Each week, teams must submit a list of contracted players to the league office by 4 p.m. ET on Thursday. The list includes the players who were drafted in that year's draft class (i.e., first-year players) and also includes all players from previous years who still have contracts with the team. The team can add up to five former rookies and three former backups to its active roster each week. A sixth rookie can be added if the team cuts one of its own players to reach the maximum active roster size of 75 players.