From the video

Video: Ranking Every Week 1 Running Back as a Sit or Start
I'll throw Kenneth Gainwell into the dub flex category because I think this is a game that you kind of just want to attach pieces to. You also have pretty banged up Tampa Bay wide receiver group right now.
Mentioned at 18:21 – 20:03Captured by STACKED 6 hr after posting

STACKED’s take

Positive signalUsage

Dub flex play with potential pass-catching volume

Kenneth Gainwell is a 'dub flex' option for Week 1; the team is expected to force usage for him early, and injuries to the wide receiver corps (including Jaylen McMillan and Acha Ibuka) may force the team to lean on running backs for pass-catching duties.

Kenneth Gainwell headshotKenneth GainwellRB · TBPlayer page — value, ADP, projections, and every insight