The NFL announced a new official change to team rosters that will give every franchise 10 spots on the practice squad, up from eight in previous seasons, per USA Today's Tom Pelissero:
Practice squad increase to 10 spots is official. That's an extra 64 jobs. Minimum per-week pay this season is $6,300 ($107,100 for season).
— Tom Pelissero (@TomPelissero) August 19, 2014
Practice squad players are just that: players who only practice. They are not active during games at all, and they can be released by their team at any point. However, any other team can sign a player off of another team's practice squad at any time. Practice squad players are paid weekly.
Many players fighting for roster spots in camp will be glad to hear of the increase of two extra slots per team, since cutdown period is already brutal. Right now, teams are at 90 players on rosters, but that limit is 75 on Aug. 26, the first cutdown period. All NFL teams must then reduce rosters to 53 a few days later on Aug. 30, two days after the final preseason games on Aug. 28.
Per the NFL's rule changes on practice squad eligibility:
First, a player must have a minimum of six games - up from the current three games - on a Practice Squad in order for that season to count as one of the player's three permissible seasons of Practice Squad service.
Second, each club will be permitted to sign a maximum of two Practice Squad players who have earned no more than two accrued seasons of free agency credit. Absent this exception, a player who has earned one or more accrued seasons would not be eligible for a Practice Squad unless the player spent fewer than nine games on a club's 46-player active list in each of his accrued seasons.