The Seattle Seahawks signed undrafted rookie fullback Jackson Acker to their practice squad on Monday alongside tight end Josiah Deguara. Deguara has more pedigree as a former third-round draft pick, but Arnold could help unlock their dormant run game in Week 7.

Acker stands just 6-foot-½ inch but weighs 242 pounds. He’s got plus speed for the fullback position, running a 4.68 40-yard dash and 2.70 20-yd split. Those rank in the 80th and 82nd percentiles among all draft-eligible fullbacks since 1987. That size-and-speed combo suggests run-blocking potential on paper. He’s short enough to get a low center of gravity, stocky enough to meet front-seven defenders in the hole, and fast enough to generate power to knock them back. His speed also allows him to get open in the passing game.

The Seahawks’ offensive line got dominated on the line of scrimmage by the Denver Broncos’ defensive line on Thursday Night Football in Week 6. The box score shows they rushed for 113 yards on 26 attempts, good for 2.3 yards per carry — but the tape tells an entirely different story.  Current workhorse running back Emanuel Wilson consistently missed opportunities for extra yardage with narrow vision and poor spatial awareness. Wilson’s -22 Rushing Yards Over Expected (RYOE) was the 15th-worst single-game mark by a running back this season, according to NFL Pro. He owns three of the bottom 16 marks this season.

Offensive coordinator Brian Fleury has struggled to stretch opposing defenses so far in 2026. In his experience with the San Francisco 49ers, they coped with similar issues through higher fullback usage. Acker’s speed tool is valuable beyond immediate need, but his box presence could be called on as early as this weekend.

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