No — Josh Jacobs will not be playing in Week 1. He was placed on the Commissioner's Exempt List on August 30, 2026, which prohibits him from practicing or playing for the Packers until the league completes its review. His Week 1 availability (Sept. 13 vs. Minnesota) is described as "highly uncertain," and realistically, it means he's out for the opener (from the Josh Jacobs page).
With Jacobs sidelined, MarShawn Lloyd is the primary lead-back candidate to target in fantasy, with Chris Brooks and newly-acquired Kaleb Johnson also in the mix for Week 1 carries.