Liviu Bird looks back on the 2015 MLS season, with his top 15 storylines from the league's 20th campaign.

Major League Soccer expanded to 20 teams as the league turned two decades old, and it ended with Cascadia winning its first MLS Cup. The Portland Timbers ended the season by defeating Columbus Crew SC, 2-1, in the final, but the 2015 talking points extended onto both sides of the March-to-December season.

The new collective bargaining agreement was agreed upon just before the first game was scheduled to kick off, spawning a light version of free agency and targeted allocation money, among other effects. Two more franchises also joined the fray, with New York City FC and Orlando City SC both failing to make the playoffs.

Before Didier Drogba moved to the Montreal Impact in July, the club made a run to the CONCACAF Champions League final. It was the closest an MLS team has come to winning the continental competition since Real Salt Lake’s 2011 loss at the final hurdle.

Big-name players kept flooding into the league, with Andrea Pirlo, Frank Lampard and David Villa stocking NYCFC’s roster, and Giovani Dos Santos making his way to L.A. Drogba scored in nearly every game after joining, and Sebastian Giovinco lit up opponents for 22 goals and 16 assists to lead MLS in both categories and set a single-season record for combined goals and assists.

Meanwhile, MLS continued signing television deals to have its action broadcast all over the world, its appeal increased by continued imports and a rising standard of play. Eurosport and Sky Sports brought the league to Europe, while Fox expanded its coverage to sub-Saharan Africa, Latin America and the Caribbean.

Here are 15 of the top storylines from the 2015 MLS season, in no particular order:

CBA agreed upon with hours to spare

We almost didn’t even have a 2015 MLS season to discuss, or at least not a full one. Negotiations on the new collective bargaining agreement between the league and players union went down to the last possible minute, with a player strike looming until the moment both sides agreed terms.

The results included a limited form of free agency, which one player in the room told SI.com “barely helps the current group of players.” It’s hard to argue when only about 10% of the player pool meets the requirements for free agency, but it still marked progress from where the league stood previously.

The new deal will be in place for five years, and it also provides for a rising league minimum salary and overall salary cap each season. The full ramifications of the new CBA still aren’t completely known, as details and new mechanisms continue to trickle out from the proceedings.

TAM encourages greater spending

One such mechanism that came from the new CBA was the addition of targeted allocation money. After giving each teams $500,000 initially, the league announced early in the off-season that it would increase that amount by $800,000 each for the 2016 and 2017 seasons–a total boost of $32 million over two years.

Targeted Allocation Money: MLS explains newest acquisition method

TAM is designed to incentivize spending on players making near Designated Player money, essentially in the middle class between the minimum earners and big-name stars making millions. In addition, all franchises will be given incremental $125,000 per season to sign homegrown players.

As with any roster rule in the league, both good and bad implications exist here.

It’s another artificial means of controlling spending—as is common in leagues with a salary cap—but at least MLS has recognized that the gap between its lowest and highest earners needs to close much faster.

Best footballing sides, not highest-spending, make final four

The Timbers and Crew only each had one player making more than $1 million, according to the latest MLS Players Union numbers. Each organization’s smart spending ensured they had balanced squads that could win matches even when they were missing their best individuals.

Portland, Columbus both spend wisely to cultivate their MLS Cup rosters

Diego Valeri and Will Johnson missed stretches of the season for Portland, for example, but the team still found a way to be dangerous without them. For Columbus, it was Ethan Finlay’s breakout season and Kei Kamara’s inspired return to the league that carried the team.

The chaotic final itself didn’t necessarily show it, but these were two of the most substantial sides in the league, along with the semifinalist Red Bulls and Dallas.

They made their success on collective, rather than individual, results.

Red Bulls go from turmoil to triumph

The season started with a fair amount of turmoil for the New York Red Bulls, who fired coach Mike Petke and hired Jesse Marsch after Ali Curtis took over as sporting director. Curtis promised change, led by his magic binder that contained the blueprint, but fans didn't much care when they voiced their displeasure at a town hall meeting early in the year.

Man with The Plan: Inside Ali Curtis's task of revamping the Red Bulls

They would come around, though, as the Red Bulls started slashing through MLS opponents on the way to their second Supporters' Shield victory in three seasons.

Marsch's high-pressing system, an alternate version of those used at other Red Bull clubs, gave the team its best point total in franchise history and the top seed in the playoffs.

Marsch's team fell short in the playoffs, but looking back on its path from March to December, the result doesn't seem all that disappointing. With a more stable core group of players and a boatload of homegrown signings since the 2015 season ended, the Red Bulls could easily be right in the thick of it again for much of the foreseeable future.

Tight final table sees parity ruling supreme again

MLS’s standard of parity didn’t slip in 2015, as the Red Bulls squeaked out their Supporters’ Shield win over FC Dallas on goal difference, and the other 10 playoff teams were separated by just four points in the standings. The Western Conference featured a tie for second and a three-way tie for fourth that came down to tiebreakers to decide seeding.

At the same time, only those top two teams won half or more of their games. As the league intended with its design, any team truly could beat any other team.

Some of the more shocking results of the season reflected that. The San Jose Earthquakes won 5-0 at Sporting Kansas City in August, and the Timbers rode the momentum of their 5-2 win against the LA Galaxy in October all the way to lifting the trophy.

Giovinco lights up MLS in record-breaking first season

Giovinco, the league's MVP, played his way back into the Italian national team picture with an astounding season with Toronto FC that led his franchise to its first playoff berth.

MLS commissioner Don Garber Q&A: On 20th season, expansion, more

His combined 38 goals and assists set a new single-season MLS record, and he also won the Golden Boot as the league’s top scorer (his assist total gave him the tiebreaker over Kei Kamara, who also scored 22 goals in the regular season). His involvement in two or more goals in 12 matches was also the most of any player in league history, and he became the first individual to score more than 20 and assist more than 10 in one year.

He might not be the biggest brand-name to sign with an MLS team in 2015, but Giovinco’s commitment to his team and not just his massive paycheck was also refreshing to see. Case in point, after playing in a Euro qualifying, fresh off a trans-Atlantic flight, he drove straight to the stadium, came on as a substitute and scored one of the best goals of the season with his run through the Red Bulls defense on Oct. 14.

Officiating still under wrong kind of spotlight

A series of high-profile incidents involving MLS officials and participants took over the headlines at various points of the 2015 season. The most innocuous included post-game comments from players and coaches, with two instances of player reactions on the field serving as the most extreme.

Clint Dempsey ripped up referee Daniel Radford’s notebook in the U.S. Open Cup after the inexperienced official showed Micheal Azira a red card in the Sounders’ match against Portland in June. Jermaine Jones shoved Mark Geiger, who has a little more experience considering his 2014 World Cup showing, in a playoff game in October.

The league rightfully suspended both players for their actions (Jones has a six-game ban waiting for him wherever he signs), and it continues to fine those who speak ill of the officiating in the media as well. But rather than pure punishment, it might be time for MLS to also consider its players’ and coaches’ words and take action to improve the poor level of refereeing as well.

RSL gutted as historically successful franchise turns page

After losing the formidable team of general manager Garth Lagerwey and head coach Jason Kreis over the past two years, an exodus of players from the Salt Lake Valley left the franchise in a shaky position. Add to it the departures of Fabián Espíndola, Will Johnson, Ned Grabavoy, Chris Wingert, Nat Borchers, Carlos Salcedo and Robbie Findley in the same time period (as well as Jámison Olave’s, but he returned), and it’s no mystery why RSL missed the playoffs in 2015.

New coach Jeff Cassar and the veterans left behind, including Kyle Beckerman and Nick Rimando, had to work through an identity crisis that plagued the team for much of the season. In the end, the streak of seven straight playoff appearances ended, which was the longest active streak in the league.

The team’s saving grace for the season came in a very successful Champions League group stage. It wasn’t a particularly difficult group with Guatemala’s Municipal and Santa Tecla of El Salvador, but winning it will ensure an early preseason and difficult matchup with Tigres to kickstart what Cassar and his men hope will be a return to former successes in 2016. They'll have to do it without Luis Gil, who left on a free transfer Wednesday to sign with Queretaro in Liga MX.

NYCFC, Orlando endure expansion struggles

Kreis’ new team, finally getting its long-anticipated debut season in MLS, didn’t have the greatest start. It ended with Kreis being fired and Patrick Vieira appointed in his place in a move that historically hasn’t worked out great for MLS teams: bringing in a European manager who has no experience, playing or coaching, in the U.S.

From Patrick Vieira's perspective, NYCFC a calculated coaching step

To put it mildly, City Football Group operates a little differently than the rest of the league.

It seemed in 2015 that CFG was more concerned with the big club in Manchester than any of its subsidiaries, keeping Lampard abroad even though he supposedly signed a contract to be at NYCFC at the start of the season, and bringing in Pirlo when he didn’t really fit what was happening on the field.

Finally, playing home games in Yankee Stadium worked out from an attendance standpoint, but the fact that it’s one of the most distinctive atmospheres in the league doesn’t make up for the fact that it’s not a soccer stadium. The continual—and thus far unsuccessful—search for a stadium site has been mired in New York City politics from the start, and there is still no end product in sight.

Orlando City, meanwhile, put a heavy emphasis on its younger players in its first MLS season. Kaká proved to be a great mentor and leader for a number of them, and the Lions missed out on the playoffs by just five points while putting together a pretty exciting inaugural effort.

MLS top rookie Larin ready to build upon club success for Canada

The club seems to have won supporters over, beginning with a crowd of 62,510 on opening day against NYCFC and carrying that impressive atmosphere throughout.

Cyle Larin, the No. 1 pick in the 2015 MLS SuperDraft, broke the league rookie goalscoring record (which now stands at 17) and finished with well over 90% of the votes to win Rookie of the Year.

The first off-season hasn’t been quite as smooth, though. A series of front-office moves and a possible threat to head coach Adrian Heath’s job have fans swinging the other direction, and the club will have multiple questions to answer ahead of the 2016 season.

Montreal falls short in Champions League final

It was a far more unexpected run than RSL’s in 2011, but the Impact came just as close to winning the Champions League in 2015. A pragmatic, smash-and-grab style carried Montreal through difficult series against Pachuca and Alajuelense as most MLS teams were still finding their feet.

America goes to Canada, wins another CONCACAF CL crown for Mexico

The magic ended in the home leg of the final, though, much as it did for RSL four years prior. After a 1-1 draw with Club América in Mexico City, which would have been a win but for Oribe Peralta’s 88th-minute equalizer, the Impact ran out of steam and lost 4-2 to give the series its final 5-3 tally.

Despite Drogba’s insane strike rate carrying the team into the playoffs, the rest of the season was a much more muted affair.

Coach Frank Klopas was fired toward the end of August as Montreal kept slipping in the standings, and the Impact lost in the Canadian Championship final in its attempt to return to the Champions League.

Chicago rebuilding after another tough year

Frank Yallop is out, the MLS stalwart getting fired from the Chicago Fire managerial position after winning just 13 of 63 league games with the team. Rather than tasking another of MLS’s well-known and tested coaches with rebuilding, though, Chicago turned to the man who led Serbia to its Under-20 World Cup championship in 2015, Veljko Paunović.

Rodriguez puts faith in Hauptman, sets out to rebuild Chicago Fire

​Paunović played for the Philadelphia Union and marks a severe change of course not just for the Fire but for all of MLS. He’s a young, foreign coach that has no track record of any kind at the club level, though his playing experience in MLS should help him.

Also, after a couple dreary seasons in the Windy City, he’s also the kind of bold hire that could come out to look like a genius move by new general manager Nelson Rodríguez.

It’ll be interesting to see if Paunović can get Chicago to play the same precise possession game his young Serbian team showed at the World Cup.

Drama takes over on Decision Day

MLS went the way of the World Cup and leagues abroad in 2015, having every game with similar implications on the final day of the season kick off at the same time. Eastern and Western Conference matches had their own time slot, with the only exception being that the two teams fighting for the Supporters’ Shield would also begin at the same time.

MLS’s inaugural Decision Day a rousing success as drama abounds

In other leagues, games with championship and relegation implications often kick off at the same time, and the final group matches of every major tournament begin simultaneously as well.

It’s partly to prevent teams tampering with the table by agreeing to mutually beneficial results, but in MLS, it adds another wrinkle to the playoff chase.

The result was a rousing success as teams continually shuffled places as they traded goals, and by the time the final whistles blew across the country, the discussion only continued rather than ending with the games. The league confirmed this format would return in 2016, and it should once again be a highly anticipated day on the calendar.

League continues expanding its worldwide audience...

After announcing new television deals with North American broadcasters in 2014, MLS expanded its worldwide portfolio by adding a number of foreign partners to show their games in 2015. Sky Sports in England and Eurosport on the European continent were the biggest additions, but MLS is now available in 140 countries and territories around the world.

The latest announcement came in November, when Fox Sports added Sub-Saharan Africa to its broadcast region. A month earlier, Fox and MLS announced that the network would also show games in Mexico, Central America, South America and the Caribbean.

Letv Sports became MLS’s official live streaming partner in China in May, and Abu Dhabi Sports Channel and Globosat joined the party in March for the Middle East and North Africa and Brazil, respectively. Beyond the broadcast booth, MLS also added Etihad Airways in 2014 and Audi ahead of the 2015 season as partners, with Etihad sponsoring the league’s Player of the Month award in 2015.

...but still insists on playing through FIFA dates

The weekends on the MLS calendar that still produce the most groans are those that fall on FIFA dates. The league continues to insist on playing matches during most international windows, although the November playoff dates comprise one notable moratorium.

Golazos, post PKs, controversy: Top 15 moments in 2015 MLS playoffs

MLS will also take a two-week break during the special 2016 edition of Copa América, which will be hosted in the U.S., but once World Cup qualifying starts up again, the league will likely play through it.

Commissioner Don Garber has confirmed that the approach could change ahead of the 2017 season, and the 2015 year provided a good example of why it desperately needs to do so.

It’s one of the most obvious and easily fixed problems plaguing the league, and though proponents point to the lower attendance in midweek games that are scheduled around FIFA dates, the watered-down quality on the field likely hurts the league more. Especially as more players in the prime of their international careers come stateside, the league’s teams will only be hurt more if MLS continues playing through those windows.

Solidarity controversy puts player policies under scrutiny

The current controversy over training compensation and solidarity payments in the U.S. hits MLS the hardest. The recent hand-wringing started by Crossfire Premier accusing the league of taking the youth club’s portion of DeAndre Yedlin’s transfer to Tottenham Hotspur, and it continued with other clubs filing claims directly against MLS and its teams.

Youth clubs file for compensation, solidarity on USMNT stars' transfers

Clint Dempsey’s move to the Seattle Sounders and Michael Bradley’s transfer to Toronto have specifically been filed with FIFA as violating the governing body’s policies.

The league and MLS Players Union were represented at a meeting with U.S. Soccer, the youth clubs and other stakeholders in October, and it’s clearly an issue that could change how MLS acquires and sells players.

“MLS will be a major beneficiary of solidarity payments going forward because of the number of academy players that we have, and yet we want to be very mindful and very careful about how we go forward here,” Garber said in his State of the League conference call in early December.

This story should continue to develop in 2016.