| Club: | Seattle Sounders FC |
| Season: | 2021 |
| League: | Major League Soccer |
| League Result: | Conference 2nd |
| Chrtitle: | General manager |
| Chairman: | Garth Lagerwey |
| Mgrtitle: | Head coach |
| Manager: | Brian Schmetzer |
| Stadium: | Lumen Field |
| Cup1: | MLS Cup Playoffs |
| Cup1 Result: | First round |
| Cup2 Result: | Canceled |
| Cup3 Result: | Runners-up |
| Cup4: | Cascadia Cup |
| Cup5: | Heritage Cup |
| League Topscorer: | Raúl Ruidíaz (17)[1] |
| Season Topscorer: | Raúl Ruidíaz (19) |
| Highest Attendance: | League: 45,737 (Aug. 29 vs. Portland) |
| Lowest Attendance: | League: 7,042 (Apr. 16 vs. Minnesota) |
| Average Attendance: | League: 25,618 |
| Largest Win: | 4–0 vs. Minnesota (Apr. 16) |
| Largest Loss: | 0–3 at Los Angeles (Oct. 26) |
| Pattern La1: | _sounders20h |
| Pattern B1: | _sounders20H |
| Pattern Ra1: | _sounders20h |
| Pattern So1: | _sounders20h |
| Shorts1: | 004eaa |
| Socks1: | 39AD04 |
| Pattern La2: | _sounders2021a |
| Pattern B2: | _sounders2021a |
| Pattern Ra2: | _sounders2021a |
| Pattern Sh2: | _orange_stripes |
| Pattern So2: | _3_orange stripes |
| Leftarm2: | 101b3d |
| Body2: | 101b3d |
| Rightarm2: | 101b3d |
| Shorts2: | 101b3d |
| Socks2: | 101b3d |
| American: | true |
| Prevseason: | 2020 |
| Nextseason: | 2022 |
The 2021 Seattle Sounders FC season was the club's thirty-eighth year of existence, and their thirteenth season in Major League Soccer, the top flight of American soccer. The team was under the management of Brian Schmetzer in his fifth full MLS season as head coach of the Sounders. Seattle were the reigning Western Conference champions and lost to Columbus Crew SC in the MLS Cup 3–0.[2]
Due to the COVID-19 pandemic, the capacity of Lumen Field was limited to 7,000 in March and increase in stages. The stadium's full capacity was restored in July with the addition of COVID-19 testing and vaccination requirements.[3]
The Sounders finished second in the Western Conference and qualified for the 2022 CONCACAF Champions League as a result. They were also runners-up in the 2021 Leagues Cup, losing to Club León in the final.
See main article: 2020 Seattle Sounders FC season.
The Sounders lost the MLS Cup at Mapfre Stadium to Columbus Crew SC 3–0. The team is set to play in the Leagues Cup, along with regular MLS and U.S. Open Cup matches.
The Sounders released or traded several key players, including six who were at the MLS Cup, during the 2020–21 offseason as part of roster moves.[4] The team began their preseason training camp at Starfire Sports in late March and played scrimmages against their USL affiliate, Tacoma Defiance, and the Portland Timbers.[5] A third match against Phoenix Rising FC was cancelled due to the spread of COVID-19 among their players.[6] The Sounders were scheduled to continue their preseason in the Los Angeles area, playing friendlies against USL clubs LA Galaxy II and San Diego Loyal,[5] but remained in Seattle. The team won two friendlies on April 10 against San Diego at Lumen Field, which was open to 200 healthcare workers in attendance.[7] [8]
Coach Brian Schmetzer switched the team from their traditional 4–2–3–1 formation to a 3–5–2 or a 3–4–1–2 to address several roster issues, namely the absence of Jordan Morris and Nicolás Lodeiro due to injuries.[9] [10] The Sounders opened the MLS season by winning or drawing in their first 13 matches—setting an MLS record for the longest unbeaten streak to open a season.[11] A reduced capacity of 7,000 seats was permitted for home matches at Lumen Field; the tickets were primarily distributed to existing season ticket holders.[12]
See main article: 2021 Major League Soccer season.
See main article: 2021 MLS Cup Playoffs.
See main article: 2021 Leagues Cup.
See main article: 2021 U.S. Open Cup.
Numbers after plus-sign(+) denote appearances as a substitute.
|-! colspan=14 style=background:#dcdcdc; text-align:center| Goalkeepers|-! colspan=14 style=background:#dcdcdc; text-align:center| Defenders|-! colspan=14 style=background:#dcdcdc; text-align:center| Midfielders|-! colspan=14 style=background:#dcdcdc; text-align:center| Forwards|-! colspan=14 style=background:#dcdcdc; text-align:center| Players transferred/loaned out during the season
[TAC] – Defiance player
| width=30 | Rank | width=30 | Position | width=30 | Number | width=175 | Name | width=75 | width=75 | width=75 | width=75 | width=75 | Total | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | FW | 9 |  Raúl Ruidíaz | 17 | 0 | 0 | 2 | 19 | |||||||||
| 2 | FW | 12 |  Fredy Montero | 7 | 0 | 0 | 1 | 8 | |||||||||
| 3 | MF | 7 |  Cristian Roldan | 6 | 0 | 0 | 1 | 7 | |||||||||
| 4 | MF | 20 |  Nicolas Benezet | 3 | 0 | 0 | 1 | 4 | |||||||||
| DF | 94 | Jimmy Medranda | 4 | 0 | 0 | 0 | 4 | ||||||||||
| 6 | MF | 6 |  João Paulo | 3 | 0 | 0 | 0 | 3 | |||||||||
| DF | 11 |  Brad Smith | 3 | 0 | 0 | 0 | 3 | ||||||||||
| FW | 17 | Will Bruin | 3 | 0 | 0 | 0 | 3 | ||||||||||
| 9 | DF | 3 |  Xavier Arreaga | 2 | 0 | 0 | 0 | 2 | |||||||||
| 10 | MF | 10 | Nicolás Lodeiro | 0 | 0 | 0 | 1 | 1 | |||||||||
| DF | 16 |  Alex Roldan | 1 | 0 | 0 | 0 | 1 | ||||||||||
| MF | 22 | Kelyn Rowe | 1 | 0 | 0 | 0 | 1 | ||||||||||
| MF | 23 | Léo Chú | 1 | 0 | 0 | 0 | 1 | ||||||||||
| DF | 27 | Shane O'Neill | 1 | 0 | 0 | 0 | 1 | ||||||||||
| DF | 28 | Yeimar Gómez Andrade | 1 | 0 | 0 | 0 | 1 | ||||||||||