That space that Bruce Arena once called the doughnut hole of development, ages 18-23, is starting to get filled through a few different methods. Some teams are currently using PDL or NPSL teams to get more playing time for their Homegrown Player-eligible youth; others use more obscure methods (Houston has a a U23 side that only does friendlies, Toronto play their older youth in a new Canadian league). The LA Galaxy lead the way with a new path - USL PRO.

Galaxy II, or "Los Dos" as they are commonly referred to, operate as a fully pro side in the 3rd division of US soccer. Players on the roster are a combination of loanees from the MLS Galaxy, Academy players playing up and players signed directly to the USL side whose rights are not held by the MLS team.

It's an intriguing way to fill out the development path of future Galaxy players. It solves one of the two more pressing issues with American youth becoming full professionals. The first MLS side to start a pro path for their youth, they also intend to extend their Academy down to the single-digit ages, soon.

The Galaxy will be joined by Vancouver Whitecaps FC and the New York Red Bulls in 2015. Seattle Sounders FC, FC Dallas and Real Salt Lake all seem likely to join that route while other MLS teams will continue to use the current loan-to-affiliate system.

The primary advantage to having a USL PRO team is that the operating MLS club will have full control of the coaching staff, player usage and player availability. Recently Bradford Jamieson IV earned his way from Los Dos to MLS. First Team players for the Galaxy were able to learn a new position (Robbie Rogers) and others to recover from injury playing down.

Seattle Sounders FC have this opportunity, which at this time is only hypothetical, but it is something that is clearly considered. With two of their HGPs getting little playing time and several others ready to sign pro deals soon the need is clear. With Starfire being the top facility in the West at the Academy level there is less need for a new stadium as there is for RSL's eventual USL PRO entry. There are still needs to professionalize the environment, if even just for the Academy, but as Sporting Director Chris Henderson told Sounder at Heart recently, that's already happening.

"I think with these new rooms we're going to build for our Academy that they'll have their own space - locker rooms, meeting room."

But it will take more than just improving things for the U18s to see an impact from the Academy. Currently a combination of college and the PDL bridge the gap between amateur and pro. Yedlin and Kovar needed two college seasons. Okoli took three. Morris seems likely to get two. College didn't make sense for Cox and he signed with an NASL side because he wasn't ready for MLS and Sounders FC didn't have an affiliate, nor a lower level pro side.

One only need look at the current Sounders U23s to see that it isn't filling that hole. The HGP eligible player with the most minutes is Chase Hanson with 1001 minutes. The next most minutes for a potential Sounders HGP? Jordan Schweitzer with less than half of that. The highly rated Morris? Only 315 minutes. Five other possible HGPs have less than 400 minutes combined between them.

The hole isn't filled.

The USL PRO team fills that hole for players that aren't quite HGP ready, but for whom college isn't the right fit.

Players like a Darwin Jones wouldn't need to play at a community college, but instead go pro. He wasn't MLS ready a few years ago, but he was pro ready.

Soon, maybe even next year, Sounders FC will have that option for their talent and Sporting Director Chris Henderson is already thinking about how the organization might use that potential team.

He talked to Sounder at Heart about those possibilities, about the theory of how to use a Sounders II/B/Reserves in USL PRO.

About 20% of the gameday roster could be from the currently Academy playing up (this wouldn't hurt their NCAA eligibility, similar to how they play in current Reserve games), about 20% could be players from the MLS team playing down (rather than loaned to OC Blues or Charlotte or Atlanta or the Cosmos). Roughly 40% could be players signed directly to the USL PRO (Sounders FC would need to use a Discovery Claim to get their rights in MLS, other teams could do the same). Another 20% could be HGP eligible players signed to the USL side.

All of those numbers would vary based on needs. A full 40% of a gameday roster could (again this was a very hypothetical and not meant as a set of rules) be players from up (MLS) or down (Academy) that are not permanent members of the team.

Many things could change this concept. Maybe the team isn't based in the Greater Puget Sound and mobility between Academy/First Team/USL PRO isn't simple. Maybe the money or paperwork doesn't make sense. Maybe Seattle decides to just affiliate and put off a permanent decision on putting a team in Tukwila.

This is an informed theory of how it could work. It is, in many ways, how Los Dos works.

It's nearly uncharted territory. Only one of the twenty-one 2015 teams is doing this right now. But that will change. Seattle may not be on the cutting edge, but they are likely to be early adopters. Current members of the Academy and players on the outside of the 18 looking for playing time early may not be soon enough.

College soccer can not be a primary answer. Future good to great players need regular professional training nearly year round. This is what Germany did, what Spain did, what Belgium did, what France did. All of the reinventions of how great soccer playing nations became greater revolved around full time professional development for their teens to Olympic age players.

It is not magic. It takes a lot of money. Just the USSDA teams themselves cost more than a million dollars per MLS participant. A fully operational USL PRO team that focuses on U23 talent in a pro environment will at least be able to recoup some of that money (through gate/merch and maybe player sales), but it will still lose money, quite a bit of it.

The long term results maybe mean more players that play "the Sounders way." These players grow up in your neighborhood and by the time they reach an MLS 18 have 10 or more years within the overarching system.

This concept is ripe with potential, but right now it is only a theory. Hopefully it turns practical soon.