According to this Tweet from ESPN’s Adam Schefter, the NFL will increase its practice squad from eight to 10 for the 2014 season:
By next week, NFL is expected to increase size of practice squads to 10 players from 8, per source. So 64 more jobs.
— Adam Schefter (@AdamSchefter) August 18, 2014
Since that will affect everybody the same way, it’s hard to say any team will benefit more than another. The biggest benefit is players, with two more from each team assured of a job that pays at least $6,300 a week (the minimum salary for practice squad players in 2014, up from $6,000 a year ago).
But no doubt in Seattle’s case, with a pretty set roster and a lot of intriguing newcomers, that’s two more players the team can keep around in the fold after the cutdown to 53.
Here’s a good resource for the specific rules concerning the practice squad.
Worth noting again that practice squads can only be assembled after roster are cut to 53. At that point, all cut players become free agents and can sign with anyone. But usually teams are able to get back most of the players they want onto their practice squads.