Behold the building of the soccer pyramid. And more importantly, the path to the pros.

USL (no longer USL PRO after this winter's rebrand) kicks off its fifth season this weekend, and its third integrated with MLS reserve teams for the specific purpose of player development in the US and Canada. Seven new MLS-affiliated teams join six incoming independent teams in the 24-team league, whose season runs from March until September.

Be sure to check out our USL content hub throughout the season.

Below you can find blurbs on all 24, as well as links to each team website.

Arizona United SC (established 2014)

MLS affiliate: FC Dallas

2014 record:10-13-5 (9th place)

ArizonaUnited.com

Had a pretty impressive debut in 2014 after building the entire organization in about a month. United bolstered their lineup with veterans this offseason and are being tipped to be near the top of the standings this year.

Austin Aztex (debut season: 2015)

MLS affiliate: Columbus Crew SC

AustinAztex.com

Austin is back in USL this season, and are hoping to be this year's Sac Republic. The Aztex boast intriguing young prospects Mikey Ambrose and Devin Perales – both of whom left college early to go pro – as well as MLS vets Sainey Touray and Kris Tyrpak.

Charleston Battery (debut season: 1993)

MLS affiliate: Houston Dynamo

2014 record: 11-8-9 (5th place, quarterfinal round of playoffs)

CharlestonBattery.com

One of the oldest continuously run and most stable pro teams in the United States, the Battery welcome back leading scorer and 2014 All-League first team selection Dane Kelly. They'll be looking to build on an inconsistent 2014 campaign.

Charlotte Independence (debut season: 2015)

MLS affiliate: Colorado Rapids

CharlotteIndependence.com

With the Charlotte Eagles departing the league for the USL PDL, the expansion Independence have taken the slot and have drummed up considerable buzz in the Charlotte area. Their roster looks pretty strong for an inaugural playoff push.

Colorado Springs Switchbacks FC (debut season: 2015)

SwitchbacksFC.com

Led by former Colorado Rapids and Tampa Bay Mutiny defender Steve Trittschuh, the Switchbacks have flown under the radar a bit in the run up to their first season, but boast local products like Davy Armstrong on their roster.

FC Montreal (debut season: 2015)

MLS affiliate: Montreal Impact

Academie.ImpactMontreal.com

USL officially comes to Canada with the entry of all three MLS teams' USL sides this season. Given Montreal's ability to sign academy products in recent years, FC Montreal may quickly hit the ground running in year one.

READ: FC Montreal reveal inaugural team roster

Harrisburg City Islanders (debut season: 2004)

2014 record: 10-7-11 (8th place, USL PRO championship finalists)

MLS affiliate: Philadelphia Union

CityIslanders.com

The City Islanders' run to the championship game last year was overshadowed by the exploits of Sacramento, but Harrisburg may find 2015 to be a year of transition, with quite a few changes to the roster.

LA Galaxy II (debut season: 2014)

MLS affiliate: LA Galaxy

2014 record: 15-7-6 (3rd place, semifinal round of playoffs)

LAGalaxy.com/2

The pioneer of MLS clubs starting a USL side, "Los Dos" had a generally strong debut campaign and are likely to build upon it this year. Their trend to sign academy products directly to the squad will likely become the pattern for other teams.

READ: Los Dos sign academy products Amaya and Martin

Louisville City FC (debut season: 2015)

MLS affiliate: Orlando City SC

LouisvilleCityFC.com

Gaining entry in the league from MLS affiliate Orlando City SC, who made the jump up this year, Louisville City look set to make an imprint in the region and will rely on the likes of MLS and USL-experienced Conor Shanosky and Matthew Fondy.

New York Red Bulls II (debut season: 2015)

MLS affiliate: New York Red Bulls

NewYorkRedBulls.com

One of the last debutants to formally announce their entry for 2015, NYRBII are something of a mystery at present, though Metro native and longtime MLS veteran John Wolyniec has been tapped to coach the team.

OKC Energy FC (debut season: 2014)

MLS affiliate: Sporting Kansas City

2014 record: 9-14-5 (10th place)

EnergyFC.com

OKC had what can be considered a typical inaugural season last year, as they missed out on the playoffs. With a season under the team's belt, Jimmy Nielsen's side will likely be much improved, and have a good shot at the postseason.

Orange County Blues FC (debut season: 2011)

2014 record: 9-18-1 (13th place)

OCBluesFC.com

The Blues are looking to bounce back from a dismal season and have completely changed their coaching staff, with Oliver Wyss taking the helm. The question is whether they have the talent to compete with USL's best sides.

Pittsburgh Riverhounds (debut season: 1999)

2014 record: 9-14-5 (11th place)

Riverhounds.com

Pittsburgh seemed to need to shake things up after a poor season last year, and bringing in former Charlotte Eagles coach Mark Steffens may be what the doctor ordered. Don't sleep on a Riverhounds resurgence at the beautiful Highmark Stadium on the south bank of the Monongahela River.

Portland Timbers 2 (debut season: 2015)

MLS affiliate: Portland Timbers

Timbers.com/t2

Given the strong support shown for the MLS Timbers and NWSL's Portland Thorns, Timbers 2 should receive considerable attention locally. There's still work to do on the roster, but the man in charge – former Wake Forest coach Jay Vidovich – was long considered one of the best minds in college soccer.

Real Monarchs SLC (debut season: 2015)

MLS affiliate: Real Salt Lake

RealMonarchs.com

Most of the attention on Real Monarchs leading up to their first season has been on their search for a stadium site, but the strength of the organization, including at the academy level, should help stock the roster with good players.

READ: RSL owner in talks with West Valley City on stadium project

Richmond Kickers (debut season: 1993)

MLS affiliate: D.C. United

2014 record: 13-3-12 (4th place, semifinal round of playoffs)

RichmondKickers.com

Richmond haven't missed a postseason berth since way back in 2003, but the club, recently among the best during the regular season, are attempting to break through and actually compete for the USL championship this time around.

Rochester Rhinos (debut season: 1996)

MLS affiliate: New England Revolution

2014 record: 10-10-8 (6th place, quarterfinal round of playoffs)

RhinosSoccer.com

The Rhinos haven't generated a great deal of buzz for the coming season, and still have to announce more of their roster. Does that signal a down year in the making, or the club playing its cards close to the vest? To be determined.

Sacramento Republic FC (debut season: 2014)

MLS affiliate: San Jose Earthquakes

2014 record: 17-7-4 (2nd place, USL PRO champions)

SacRepublicFC.com

How do you follow up a title-winning first season? That's the dilemma facing Sacramento Republic, who took the league, and the local community, by storm in 2014 on their way to the USL PRO championship.

Saint Louis FC (debut season: 2015)

MLS affiliate: Chicago Fire

SaintLouisFC.com

With the St. Louis region having been long one of the best soccer areas in the US, it's long overdue for a pro team to return. They should have plenty of community involvement, and will likely play a direct brand of soccer that may take off right away.

Seattle Sounders FC 2 (debut season: 2015)

MLS affiliate: Seattle Sounders

SoundersFC.com/s2

As you would expect for an organization with Garth Lagerwey at the helm, Seattle are thinking long-term with the construction of S2, conceiving of the two pro teams as one unified group. The USL side will probably perform immediately, but results matter less than player development.

READ: Path to the pros a familiar one for S2's McCormick

Toronto FC II (debut season: 2015)

MLS affiliate: Toronto FC

TorontoFC.ca/tfcII

TFCII, like many teams, are still working on their roster, but they appear to be challenging their MLS draft picks to prove themselves on the USL level first for 2015. Along with that, local talent should bolster the squad quickly.

READ: Three more TFC academy graduates make the leap to TFCII

Tulsa Roughnecks FC (debut season: 2015)

TulsaRoughnecksFC.com

The latest American franchise to hearken back to the original NASL with their team nickname, the Roughnecks may be the next team to come out of nowhere (from the national media's perspective) and take off in their region. We're looking forward to the first Oklahoma Derby.

Vancouver Whitecaps FC 2 (debut season: 2015)

MLS affiliate: Vancouver Whitecaps

WhitecapsFC.com/wfc2

The Whitecaps' academy is arguably the strongest in Canada but that hasn't led to as many Canadian players featuring for the first team as expected. WFC2 could become one of the best at player development very quickly.

READ: Q&A with new Whitecaps FC 2 head coach Alan Koch

Wilmington Hammerheads FC (debut season: 1996)

MLS affiliate: New York City FC

2014 record: 9-8-11 (7th place, quarterfinal round of playoffs)

WilmingtonHammerheads.com