The expansion of the practice squad from eight to 10 players took place ahead of the 2014 season with the agreement in place for two seasons. The two sides agreed to extend the 10-player cap for another two years while making one slight change.
In the last two seasons, teams were allowed to include two players with two accrued seasons on the practice squad; for this season and next, that's been bumped up to four players.
An accrued season is reached when a player is active for six or more regular season games. Some more detail on accrued season details and PS rules:
A player can also go to the practice squad with an accrued season provided they were on the 45-man active roster for less than nine-regular season games.
In addition, a player is allowed on the practice squad for two years. If a player is on the practice squad for six weeks, up fron three weeks per the previous agreement, in a season, it is considered a year of PS sevice. Players are only allowed to be on a practice squad for a third year if their team keeps 53 players on the active-inactive list at all times.
For reference, to start the 2015 season the Rams practice squad consisted of OT Isaiah Battle, RB Malcolm Brown, FS Christian Bryant, TE Justice Cunningham, SS Jacob Hagen, FB Zach Laskey, DE Matt Longacre, CB Trovon Reed, DT Louis Trinca-Pasat and DT Doug Worthington.