Not much has changed between this year and last.
That's 25 players in all, but the italicised players are below 21 (per the rules, born after January 1, 1989) and are therefore eligible despite not being on the official 25-man roster - Chelsea actually only named 19 players. The reason? There are only four home-grown players on the team above the age of 21: Frank Lampard, John Terry, Ashley Cole, and Ross Turnbull. This limits the amount of players the Blues are allowed to field - there are only two more spots open before the Blues are forced to meet the home-grown requirement for new acquisitions.
Is this a worry? Yes and no. Many of the kids are more or less ready to play, and I wouldn't be terribly concerned if, say, Jeffrey Bruma started 15 Premier League games this season. The squad depth isn't really restricted due to the home-grown rule: many of our games will come in non-league competitions and the rules don't mean anything there, so the 25 should be more than sufficient for league play. However, we then run into major problems with the Champions League and FA Cup. How will the team balance any injuries incurred over the year (which are already starting) with the need to do more than just play the reserves to progress? One injury to any given position is ok - the team can adapt. Two? Then things start getting dicey, and you're talking about Fabio Borini or Gael Kakuta suddenly being asked to lead the team to titles.
Clearly, the team thinks that its youth core is ready to step up and make a major contribution. The lack of further purchases as the transfer window closes is a clear vote of confidence in our youth as the Blues send out clear signals that the next generation of great talent will be coming from our academy.
I just hope that's not a mistake.