By Theo Lawson

The (Spokane, Wash.) Spokesman-Review

PULLMAN, Wash. — One of the most robust pipelines in the college football coaching world is the one that exists between the golden wheat fields of Washington’s Palouse and the evergreen forests of Oregon’s Willamette Valley.

Not since 2015 has Mike Leach made it through the offseason without seeing one of his assistant coaches swap crimson Washington State polos and caps for the green — not just apparel — that Oregon has to offer.

Jan. 13, 2016: Washington State inside receivers coach David Yost is hired by Mark Helfrich as Oregon’s new quarterback coach and passing game coordinator.

Jan. 12, 2017: Defensive line coach Joe Saleve’a leaves Pullman to coach the same position in Eugene for Willie Taggart.

Jan. 21, 2018: Reports surface that longtime Cougar running backs coach Jim Mastro has accepted an offer from Mario Cristobal to work as UO’s run game coordinator and running backs coach.

Jan. 23, 2019: Linebackers coach Ken Wilson, another one of the longest-tenured members of Leach’s staff, joins Cristobal’s staff in the same capacity.

If the situation was different, Oregon’s constant pilfering of Washington State coaches might be considered an epidemic. But, because the Cougars have stacked up four consecutive wins against Oregon dating back to 2015, and have done an admirable job of filling the vacancies left by the assistant coaches who have jumped ship, most WSU fans have gotten a kick out of the Ducks — known for their pageantry and deep pockets — picking off Leach’s assistants year after year.

“If you can’t beat them, buy them,” one fan offered on Twitter on Monday afternoon.

The 11th-ranked Ducks (6-1, 4-0) are two-touchdown favorites to beat the unranked Cougars (4-3, 1-3) this Saturday at Autzen Stadium, and this does seem to be Oregon’s best chance in recent memory to end the skid against WSU.

Yost left Oregon when Helfrich was fired and has had two stops since, but the three other ex-WSU assistants — Salave’a, Mastro and Wilson — will be on hand when the Pac-12 North foes clash in Eugene.

“They have brought on quite a few. I don’t know, they ought to just call me up and I’ll see if I can help them with anything they need,” Leach quipped Monday.

“‘Oregon, what are you looking for?’” Leach said, imitating an imaginary conversation between the Washington State coach and Cristobal. “‘Yeah, well I’ll see if I can help you.’ That’s what I need to do.”