TUKWILA — The screen saver on Brian Schmetzer’s computer is an image of Portland coach Caleb Porter glaring over at the Seattle bench after a Timbers goal in last year’s playoffs.

The expression on Porter’s face by now is burned in Schmetzer’s memory, and it serves as daily motivation for the Sounders assistant coach.

So sure, nearly five months have passed since the 2013 Western Conference semifinals, a two-game series Portland won 5-3 on aggregate, but the wounds are still fresh heading into Saturday’s noon game at Providence Park.

“It’s going to be intense,” said coach Sigi Schmid. “It’s going to be usual Portland-Seattle, and, yeah, last November stays with us a little bit.”

The emotions in this, the greatest rivalry in MLS, will never waver. Nearly 40 years of antagonism, dating to 1975 in the North American Soccer League, makes it so.

The offseason, though, has brought somewhat of a new dynamic to the series.

Three players joined either the Sounders or Timbers the past few months having previously played on the other side of the rivalry: Seattle’s Kenny Cooper played in Portland in 2011 and new Timbers additions Steve Zakuani and Andrew Weber have also represented the Rave Green. All three could be in action Saturday, though Zakuani is questionable with a sore hamstring.

Only two players had played in Seattle and Portland over the first three years of the MLS chapter of the rivalry — Mike Fucito and Adam Moffat, though neither was featured extensively during their time in the Pacific Northwest and both have since moved on.

So how does an influx of players who have held allegiances with the “enemy” affect the rivalry?

Schmetzer has some experience on the matter from when he coached the Sounders of the United Soccer Leagues. Seattle signed an ex-Timber in Hugo Alcaraz-Cuellar en route to the league championship in 2007 but also saw Andrew Gregor bolt for Portland that year.

“I don’t know what Andrew was thinking there,” Schmetzer quipped. “But to answer your question, I think it just spices up the rivalry.”

Cooper, a popular interview subject in this game’s buildup, has embraced the positives of having played for both teams. The 29-year-old forward, one of the top 20 scorers in MLS history, led the Timbers with eight goals in 2011 and netted his first for the Sounders last week.

“These are the games we all dream of playing in when we were kids,” Cooper said. “For me, it was a dream come true to have been a part of this rivalry back in the day when I was with the Timbers. Everything from the tifos to the buzz in the streets before the game, it’s all super special.”

The importance to fans is at the core of the teams’ motivations when regional bragging rights are on the line, but both sides are also in need of points. Portland, which boasted the Western Conference’s best record last year, is off to an 0-2-2 start and hasn’t even held a lead this season.

The Sounders have lost two of their past three games, not to mention three in a row against the Timbers.

It’s not like the pressure can be much greater, though.

“In this rivalry,” said Schmid, “the league games are like playoff games, and the playoff games maybe go to another different level, but it’s hard to imagine it going to a level higher.”

Note

• Porter, the Portland coach, was fined an undisclosed amount by MLS for strong criticism of the referees earlier this week. Porter suggested the assistant referee during the team’s last game, who was primarily responsible for a red card (since rescinded) to Michael Harrington, was “trying to be the show.”

Joshua Mayers: 206-464-3184

or jmayers@seattletimes.com.

On Twitter @joshuamayers