The first indicator that it is not designed to go to Willson is alignment. If they were trying to isolate him for a slant, he would have lined up wider and stayed clear of all the "junk" in the middle. The concept we ran is most commonly used against zone. Willson would run a post, the inside LB would either drop back and take it away or stay up and honor Fred. Fred starts outside first, which the LB could read as a route to the flats, and thus go back to cover Willson. In that scenario, when Jackson angles back inside, there is a nice void there and he walks in to the end zone. If the LB had stayed up to take away the angle to Jackson, it would create a void behind him for an easy TD for Willson. Common high-low zone beater.
I say that Jackson was the primary in this situation because you don't love Willson's matchup against man coverage there. Willson also quits on his route awfully early and heads back outside even though Russell rolls left, to make sure he doesn't stomp on Jackson's route. You do, however, like Jackson angling back inside against a LB, and given another second, we did have an easy TD there.
I just can't think Russell believed the OLB was coming. And I can't figure out what he didn't like about going to Baldwin. Maybe he just really liked the Fred Jackson matchup, but either way, I think it is incredibly unlikely that Luke Willson was his primary read.