All around the NFL, teams are paring down rosters to the mandatory 53-man limit before the league’s deadline on Aug. 31 at 4 p.m. ET. Beginning on Sept. 1 at 1 p.m. ET, teams can start assembling practice squads, groups of 10 players who practice with the team throughout the week but are not eligible to be active on game days.

Many times, teams use practice squads to keep players who have potential but need development. It gives teams an opportunity to invest in players in a low-cost (by NFL standards) and low-risk way. It also provides teams with a stash of backup players who are familiar with the scheme and system, which is helpful in the event of injury.

The NFL has tweaked its rules for practice squad eligibility in recent years. In 2014, the NFL and NFLPA agreed to a rule that expanded the practice squad roster limits from eight to 10 players. In addition, teams previously were allowed just two of the 10 practice squad spots to be filled by players who had two or more years of experience on an NFL roster. Now, that number has been increased to four players.

Here’s a brief rundown of who can be signed to a practice squad and what it means for his NFL career.

Who is eligible for a spot on the practice squad?

Each team can keep 10 players on its practice squad. Eight teams are allowed an 11th player as part of the league’s International Player Development Program.

Up to four of those 10 players can have two accrued NFL seasons. So, was a player on the 53-man roster for at least six games of two NFL seasons? Sorry, they’re out of luck.

It used to be that three weeks of an NFL season spent on a practice squad counted as one full season of practice squad eligibility. Now, that number has been increased to six weeks, which expands some players’ eligibility.

A player can spend no more than three seasons on any practice squad.

How are practice squad players compensated?

Practice squad players must be paid at least $8,000 per week for the 2019 season. If a player is on a team’s practice squad for the entire regular season, that amounts to $136,000 for the year.

Teams can pay practice squad players as much as they’d like. They’re not limited to that minimum, and practice squad salaries do count toward the cap. Most teams tend to pay salaries closer to the minimum, though.

If a practice squad player is signed to another team’s active roster, they will receive a minimum of three game checks, no matter how long they remain on that active roster. They can be cut after a week, but they’re still getting three game checks.

Does a practice squad player have to stay on the practice squad?

A practice squad player can be signed by another team, as long as the signing team adds the player to the 53-man roster. A practice squad player cannot be signed to another team’s practice squad.

A player can, however, be signed to another team’s practice squad if their original team releases them.

An opponent cannot sign a player off of a rival’s practice squad to use them to prepare for an upcoming game. Say the Saints are getting ready to play the Falcons, and Sean Payton wants to be sneaky, so New Orleans wants to sign a player off of Atlanta’s practice squad. The Saints can’t do that fewer than five days before the game against the Falcons, and if there’s a bye week before that matchup, the minimum is nine days.

While many players who spent the preseason with NFL teams are being cut today, the hope remains that they may get signed by another team off of waivers. If players clear waivers, the next best thing is the practice squad, which allows them to continue to develop as players and keep their NFL hopes alive.

It’s still a long shot for these players to carve out successful NFL careers, but landing on a practice squad gives them a shot. Several players have graduated from practice squads to active rosters and made an impact for their teams, including Broncos linebacker Brandon Marshall, Dolphins wide receiver Danny Amendola, and James Harrison.