2009 Major League Soccer season

The 2009 Major League Soccer season was the 14th season of Major League Soccer. It was also the 97th season of FIFA-sanctioned soccer in the United States, and the 31st with a national first-division league.

The Seattle Sounders FC debuted as the league's 15th club and were the second team in history to qualify for the MLS Cup Playoffs in their inaugural season. The club set a league record for attendance and averaged 30,943 per regular season match at Qwest Field.

After three seasons, the MLS Reserve League was discontinued. As a result, each team's Developmental Roster spots were reduced from 10 to four, and each team's Senior Roster spots were increased from 18 to 20. This had the effect of reducing each team's total roster from 28 to 24 players.

The regular season began on March 19, and concluded on October 25. The 2009 MLS Cup Playoffs began on October 29, and concluded with MLS Cup 2009 on November 22. Real Salt Lake won their first MLS Cup by defeating the Los Angeles Galaxy in a penalty shootout.

Season format
The season began on March 19 and concluded with MLS Cup on November 22. The 15 teams were split into two conferences with 7 playing in the Eastern Conference and 8 playing in the Western Conference. Each team played 30 games that were evenly divided between home and away. Each team played every other team twice, home and away, for a total of 28 games. The remaining two games were played against four regional rivals, one at home and one away.

The top two teams from each conference automatically qualified for the MLS Cup Playoffs. In addition, the four highest remaining point totals, regardless of conference, also qualified. In the first round, aggregate goals over two matches determined the winners. The conference finals were played as a single match, and the winners advanced to MLS Cup. In all rounds, draws were broken with two 15-minute periods of extra time, followed by penalty kicks if necessary. The away goals rule was not used in any round.

The team with the most points in the regular season was awarded the MLS Supporters' Shield and qualified for the CONCACAF Champions League. Additionally, the winner of MLS Cup, and the runner-up, also qualified for the CONCACAF Champions League. An additional berth in the Champions League was also awarded to the winner of the U.S. Open Cup. If a team qualified for multiple berths into the Champions League, then additional berths were awarded to the highest overall finishing MLS team(s) not already qualified. Also, Toronto FC, as a Canadian-based team, could not qualify for the CONCACAF Champions League through MLS, and had to instead qualify through the Canadian Championship.

Automatic qualification for the U.S. Open Cup was awarded to the top six overall finishers. The rest of the U.S.-based MLS teams had to qualify for the remaining two berths via a series of play-in games.

Qualification for the SuperLiga was awarded to the top four overall finishers not already qualified for the CONCACAF Champions League.

Weekly awards
Save of the week was first introduced during week 10 of the 2009 season.