We are living in the era of what many people refer to as "MLS 2.0." Version 1.0 was the original 1996 version, when the teams in the new league were saddled with names and jerseys that appeared to have been stolen from a defunct roller hockey league. Version 2.0 came into being in the early 2000s, when the league recovered from early struggles and started placing teams in soccer hotbeds, teams that quickly began to eclipse those that were around in the league's humble early years.

We are headed now for version 3.0 — the mature, stable league that founders envisioned when they set up Major League Soccer. What that means for local fans, though, and for the teams that came in during the first two versions, is not necessarily good.

Counting the impending expansion teams in Los Angeles and Miami, MLS is already at 24 teams and looking for more. Late in January, MLS officially opened up bidding for the league's next round of franchises. Twelve cities submitted bids, most complete with airbrushed stadium renderings, cautiously supportive comments from local government officials and MLS-themed Twitter hashtags.

All that's clear right now is that the league is headed at least to 28 teams, and possibly more. Such growth would rival the other four major pro sports in North America, all of which have 30 or more teams.

When that happens, what comes next is anyone's guess. MLS is already one of the world's largest first-division leagues. Most other countries' first-division leagues have somewhere in the area of 20 teams. One of the few to rival MLS is Argentina's league, which expanded to 30 teams in 2015. But the expanded Primera Division is so hated in that country that the league is slowly shrinking itself back to 24 squads.

MLS is showing no signs of shrinking itself, either by introducing a two-division setup or otherwise. With a dozen more cities clamoring to get into the league, there soon won't be enough teams to go around. That means one thing: Once the league hits whatever limit it might set for itself, there will be a period of franchise moves, where expansion ceases and established teams pick up and go.

Those teams in the first rounds of MLS expansion should be worried. If there's anything we've learned from other sports, particularly the NFL, it's that team owners are never happy with their current stadiums, not if there's another owner out there with a newer and shinier arena. Soon, current MLS cities may be asked to pony up again. If there's resistance, their teams may leave for markets offering more glitz.

Teams will move when MLS 3.0 gets here. The teams without soccer-specific stadiums — currently including Minnesota — or those with older stadiums in particularly far-flung suburbs, such as Chicago, are probably the most under threat.

The future of the league isn't expansion, but instability. If we've learned anything from the other American leagues, that instability never goes away.

SHORT TAKES

Paul Arriola

• For a decent snapshot of where the National Women's Soccer League is at, consider this: In the W-League, Australia's top women's soccer league, eight of the 16 players on its Team of the Season are also NWSL players. It's a testament to the quality of the NWSL, but also shows that many of the league's best players still have to play for two different teams in two different seasons.

• Many American players still are getting geared up for the MLS season, but keep an eye on Paul Arriola. The 22-year-old, who plays for Club Tijuana in the Mexican league, has scored twice and set up two more goals in the first four games of the Liga MX Clausura. He may end up playing a big part for the U.S. national team going forward, especially in World Cup qualifiers in March.

• Odd statistical note of the weekend: The Bundesliga is 23 goals from the 50,000th goal scored in league history. In typical, thorough German fashion, five paragraphs of explanation and calculations are included on the league's official website, should you care to study them.

WEEKEND WATCH GUIDE

Leicester City coach Claudio Ranieri

Bundesliga: Eintracht Frankfurt at Bayer Leverkusen, 8:30 a.m. Saturday, FS2. Bayer is still without Javier "Chicharito" Hernandez, as the club's talisman is injured. It's part of the reason that Leverkeusen is struggling this year. Frankfurt was nearly relegated last season, but a major turnaround — and the league's second-best defense — has it in third place, nearing a Champions League spot.

Premier League: Tottenham at Liverpool, 11:30 a.m. Saturday, Ch. 11. A promising season for Liverpool appears to be careening off the rails, as the Reds have won just one of their past 10 games in all competitions. A victory over Tottenham won't rescue what was supposed to be Liverpool's chance to push for the title. But it would help soothe the angry fans at Anfield.

Premier League: Leicester City at Swansea City, 10 a.m. Sunday, NBCSN. The champions are in crisis. Leicester City has lost four consecutive Premier League games while scoring zero goals. It now sits just one point out of the relegation places. A visit to Swansea City, tied with Leicester with 21 points, has major relegation implications. The league champions couldn't be relegated, could they?

Serie A: Juventus at Cagliari, 1:45 p.m. Sunday, beIN. Cagliari may be firmly stuck in the bottom half of the Serie A table. But playing there is never easy for opponents, as the team has lost just twice at home all season. Juventus is in what appears to be an easy cruise to another Serie A title, with a seven-point lead at the top. Can Caligari interrupt the coronation for at least one more week?

Writer Jon Marthaler gives you a recap of recent events and previews the week ahead. • jmarthaler@gmail.com. Online: startribune.com/soccer