Correct although its 25 over 21s. Someone could have a look at the named squads to see what, if any teams have gaps meaning that he could sign for them.
here you go: http://www.premierleague.com/en-gb/news/news/2013-14/sep/premier-league-squad-lists-201314.html But as I understand it, if a team has 25 (or more) over 21s on books and chooses not to (or fails to) register 25, they still can not register free agents at this point, so the list of registered players doesn't necessarily show if any team can register more players now. You'd have to have a complete list of players the team has on contract, registered or not.
Why would any team not register an over 21 if they had them, they cannot add anyone else so theres no point in leaving anyone out, all that would do is deprive them of being able to use that player. He can go to Arsenal (lol) the scum (lol) Everton (lol) Fulham Liverpool (lol) Man city (lol) Newcastle (if he gets himself a stripey t shirt) Norwich Saints Stoke Sunderland Swansea Spurs (lol) WHU So he still has 8 possible PL teams that could sign him, a lot of them have 24 man squads seemingly to leave themselves open to signing a free agent.