The hosts are winless in nine games heading into this one, while their visitors will be looking to pick up a fourth straight victory across all competitions.
Match preview
Portland Timbers were beaten for the third game running following a 2-1 defeat against Seattle Sounders when the teams faced off on Sunday.
Phil Neville's men made a bright start and opened the scoring through Felipe Mora before goals from Cristian Roldan and Raul Ruidiaz turned the game around.
As a result, The Timbers have dropped to the bottom of the Western Conference of the MLS table and are already six points adrift of playoff contention.
Coming next up is the task of facing off against an opposing outfit who boast just one victory from the last five editions of this fixture, losing three of the other four.
However, that solitary win did come in the most recent encounter back in June as Thursday's hosts fell to a narrow 1-0 defeat in a friendly encounter.
San Jose Earthquakes continued their recent resurgence thanks to a 3-2 triumph over Colorado Rapids at Dick's Sporting Goods Park on Sunday.
After going two goals down to strikes from Rafael Navarro and Omir Fernandez, Luchi Gonzalez's men hit back through Amahl Pellegrino and Hernan Lopez before Cristian Espinoza completed the comeback in the 66th minute.
With 10 points picked up from 12 matches so far, The Goonies sit 13th in the Western Conference standings, level on points with their next opponents.
Off the back of a first away win in eight outings last time out, Thursday's visitors now go in search of consecutive wins on the road for the first time in over a year.
Portland Timbers Major League Soccer form:
D
D
D
L
L
L
San Jose Earthquakes Major League Soccer form:
L
L
L
D
W
W
Team News
Portland Timbers' Marvin Loria is still battling with a long-term knee problem he picked up in January and will not play any part in this one.
The home side will also be without the services of Miguel Araujo and Claudio Bravo as they continue to nurse respective leg injuries.
Victor Costa received his fifth yellow card of the season against Colorado and will serve a one-game suspension for San Jose in this one.
JT Marcinkowski and Daniel Britto are ruled out through knee and thigh injuries respectively, while Jamar Ricketts misses out through a damaged ankle.
Portland Timbers possible starting lineup:
Crepeau; E.Miller, K.Miller, Zuparic, Mosquera; Paredes, Chara, Rodriguez; Moreno, Antony, Mora
San Jose Earthquakes possible starting lineup:
Story; Munie, Valdez, Rodrigues, Akapo; Tsakiris, Gruezo; Pellegrino, Lopez, Espinoza; Ebobisse
We say: Portland Timbers 2-1 San Jose Earthquakes
Thursday's clash between Portland Timbers and San Jose sees the two worst defensive teams go head to head, so we anticipate an open and end to end contest. We are also tipping the hosts to emerge victorious come the end of the 90 minutes.