TUKWILA — Three weeks from today, the Seattle Sounders will open their 2015 season in front of a huge crowd at CenturyLink Field, beginning another chase for the MLS Cup that has eluded them through their six-year existence.

Unless they don’t.

For the Sounders or any Major League Soccer team to begin their seasons in March, the league and the MLS Players Union need to agree upon a new Collective Bargaining Agreement to avoid a work stoppage that players say they are fully prepared to initiate if the league won’t meet some of their demands, most notably, free agency.

League and players union, you have three weeks. Figure this out.

A prolonged work stoppage is bad news for any sport; it would be devastating for Major League Soccer, a league that has grown tremendously since 1996, but that still has a ways to go. Even Major League Baseball and the National Hockey League felt long-term ramifications of work stoppages in recent decades, and those leagues are far more established, both financially and in terms of a devoted fan base, than MLS is or will be any time soon.

In soccer-crazy cities like Seattle and Portland, fans would notice the league’s absence and be upset about a strike, but they would also embrace their teams when they returned to action. In much of the country, however, a significant portion of the fanbase the league has worked so hard to grow over time will simply move on to something else and be slow to come back, if they come back at all.

The league has two expansion teams starting play this season in New York and Orlando, both of which have acquired big-name stars like Kaka, David Villa and Frank Lampard. Lukewarm markets like New England have made progress of late, and attendance, and more importantly, TV ratings, continue to make modest gains. In short, this would be a disastrous time for the league to take an unexpected hiatus.

And that’s part of the reason why players realize now is the time to fight for some significant changes, most notably some sort of free agency. Brad Evans, the Sounders’ players representative, told reporters that a “strike is imminent if we don’t get what we want.” And what they want, first and foremost, is the ability to choose where they play after putting in their time.

As it stands now, even veteran players’ rights are controlled by their current club after their contract expires. If that team doesn’t want to keep them, then they go into a reentry draft, which means another club, not the player, will choose that player’s fate.

“This will be year No. 9, and I feel like if I did want to go somewhere, I’ve earned the right to play where I want to play,” Evans said. “Whether that means playing closer to home at the end of my career for less money, or playing somewhere for a little more money, it should be up to me where I decide to play. And right now it’s not up to me. Even if my contract expires, I needed to be traded somewhere, for a bag of balls or a couple of players, whatever it is.”

The last time the league and players union sat down to negotiate a CBA, players knew they didn’t have a shot at free agency, so they focused on smaller issues. Now, however, they see a chance to fight for more significant change.

“It’s leaps and bounds from where we were five years ago,” Evans said. “Five years ago, we were so far off on where were wanted to be, so we couldn’t even think about chipping away at a topic like free agency. It was brought up, but it was like, we know we’re not going to get anything, we know the money’s not going to be there. We know the minimum might shoot up a little bit, but it’s not going to be there.

“So we needed to focus on appearance fees, per diem, free internet at hotels, better hotels, better meals at hotels. Little things like that we needed to get under our belt, so that five years later we can focus on big issues.”

Yes, players used to pay for their own internet on work trips. Even now, while things have improved, the minimum salary in 2014 was just $36,500, and most players’ contracts aren’t guaranteed.

The league counters by saying they and their clubs are still losing in excess of $100 million per year, and that free agency would drive up costs even further. MLS operates under a single-entity system, which has helped the league grow at a sustainable rate, but which also leaves players feeling like they are being sacrificed for the good the league.

Contracts are negotiated by the league, not teams, and MLS, not a free market, decides where players are allocated when they come to the league or are out of contract with a current team.

That system not only stifles free agency, it also leads to a comical lack of transparency that has players, coaches and even owners, such as Portland’s Merritt Paulson, openly criticize the way the league has facilitated the acquisition of star players by some of the league’s marquee teams.

“Our ability to best effectively compete in the international market — and this was the whole foundation of the league — is when the league functions as a single voice in that international market,” MLS deputy commissioner Mark Abbott told reporters last month.

”If the league itself is trying to decide how do we best compete against all of these international clubs, it would be more effective if the league is making those decisions, as opposed to our clubs competing with one another.”

“Our structure has provided the foundation for the growth of our league that we have seen to date, and the growth that we anticipate in the future.”

Players are understandably wary of the league crying poverty while it collects nine-figure expansion fees and while teams hand out huge contracts to star players like Clint Dempsey, Michael Bradley, Steve Gerrard, Kaka, Lampard and Villa.

“With the TV contract, the two teams coming in, the amount of money being spent on DPs is insane, $100 million on expansion fees … there’s money to be had,” Evans said. “We’ve seen the numbers, we know where we’re at, we know where they’re at, and we think that we’re not asking for something astronomical, we’re asking for something that’s fair for all the parties.”

Players, especially MLS veterans, undoubtedly deserve some significant concessions from the league they helped build into a 21-team league that just agreed to a new TV rights deal that is worth $90 million per year, according to Forbes, dwarfing the league’s previous TV deal. While the single-entity structure isn’t going anywhere yet — though it ought to be done away with sometime soon — it is time for MLS to give players some form of free agency and increased minimum salaries.

Players, on the other hand, need to recognize that they won’t get everything they want this time around, and realize that as outdated as the league’s structure may seem, it did help the league survive this long in a country that has long rejected professional soccer.

The two sides are negotiating, and fortunately there’s now a mediator involved, which should take some emotion out of the meetings. They have three weeks to figure this out, or the alternative is a work stoppage the league, and many of its underpaid players, simply cannot afford.

The big issues haven’t been settled yet, but there’s still time — just not much.

“It’s deciding where we want to give in, and what we need to stand firm on,” Evans said. “There are definitely a few issues we need to stand firm on that we haven’t even come close to yet, obviously free agency hasn’t been talked upon yet. Being the most pressing issue, you’d expect that would be the last thing to get done.

“Like any labor negotiation, it’s going to be down to the last minute. Right now we aren’t where we want to be, but there have been some positives. There have been a lot of good meetings. … Bringing the mediator in has been good, but we’re still a ways away. But there’s always time up until that last minute.”

Herald Columnist John Boyle: jboyle@heraldnet.com