On October 29, Portland re-signed midfielder Sebastián Blanco to a multiyear contract where he will remain a Designated Player.

[3] On November 15, MLS cut Portland forward, Brian Fernández, since he failed to comply with the league's Substance Abuse and Behavioral Health (SABH) Program.

[4] On November 19, Nashville SC selected left-back Zarek Valentin as the fourth overall pick in the 2019 MLS Expansion Draft.

[5] On November 20, Portland signed Croatian center-back Dario Župarić from Prva HNL side, HNK Rijeka.

Portland declined options on goalkeeper Kendall McIntosh, defender Modou Jadama and forward Foster Langsdorf.

[9] On December 10, forward Jeremy Ebobisse underwent a minor procedure to repair a meniscus tear that was sustained last month while on duty with the U.S. U-23 Men's National Team.

[10] On December 16, Portland announced the multiyear contract extension for Argentine midfielder, Diego Valeri.

He was signed using Targeted Allocation Money (TAM) and will no longer use a Designated Player (DP) slot.

[15] On January 9, Portland selected Irish midfielder, Aaron Molloy from Penn State as the 16th overall 2020 MLS Super Draft pick.

[17] On January 13, Portland selected American defender, Zachery McGraw from Army as the 68th overall 2020 MLS Super Draft pick.

[19] On January 22, Portland midfielder Andrés Flores underwent surgery to repair medial meniscus tear.

[22] On January 31, Portland signed Chilean striker Felipe Mora on loan for one year from Liga MX side Pumas UNAM.

[24] On February 6, Portland announced the completed transfer of Cristhian Paredes who was on loan to the Timbers from Liga MX side, Club América.

On February 11, Portland received $150,000 in General Allocation Money (GAM) from the Montreal Impact in exchange for a 2020 international roster slot.

During the same day, Portland acquired $165,000 in General Allocation Money from Vancouver Whitecaps FC in exchange for a 2020 international roster slot.

On March 7, Taylor Twellman reported Portland right-back Jorge Moreira sustained a leg injury that will likely require surgery.

[29] On March 8, Portland captured their first victory of the season by defeating Nashville SC with a final score of 1–0.

[34] On May 1, Major League Soccer announced that players are cleared to start voluntary individual workouts beginning on May 6.

[37] On May 30, Major League Soccer announced that clubs can begin voluntary small group training sessions.

[38] On June 4, Major League Soccer announced that clubs can return to full team training.

[40] On June 11, Portland was drawn into Group F of the MLS is Back tournament, along with Los Angeles FC, LA Galaxy, and Houston Dynamo.

[41] On June 18, Portland declined a permanent transfer option included in the loan agreement on right-back Jorge Moreira.

[43] On June 22, Portland signed defender Zac McGraw who was selected by the Timbers as the 68th overall 2020 SuperDraft pick earlier this year.

[45] On July 6, Major League Soccer announced the revised 2020 transfer windows due to the impact of COVID-19.

The goal scorers were Jarosław Niezgoda (assisted by: Sebastián Blanco and Marvin Loría) in the 7th minute.

Included in the XI were Portland's Jeremy Ebobisse, Sebastián Blanco, Larrys Mabiala, and Diego Chará.

The goal scorers were Felipe Mora in the 67th minute and Diego Valeri (assisted by: Yimmi Chará, Sebastián Blanco) in the 90th +2 On September 6, Portland defeated Seattle Sounders FC at CenturyLink Field with a final score of 2–1.

On September 8, Portland announced that Sebastián Blanco will miss the remainder of the season due to torn ACL.

On September 19, Portland secured a dominated win over San Jose Earthquakes away with a final score of 6–1.

Portland won with a final score of 1–0 with the lone goal scorer being Felipe Mora (assisted by: Eryk Williamson) in the 5th minute.