I think it's a valid question of how well he fits, I just don't see the numbers there to seriously think he'll get cut. The other EDGE defenders are:
Landry - ok, clearly above Jennings
Chaisson - low cost, 1 year FA signing who's very obviously a situational pass rush specialist as opposed to everydown guy
White - has looked completely inept as an EDGE defender setting the edge and looks better as an inside rusher, at least situationally
Swinson - day 3 draft pick rookie who projects to be a pass rush specialist first rather than every down guy, if he ever does become anything
Jennings edge setting really is a unique skill set in that position group and 5 EDGE defenders is hardly a lot to keep, especially factoring in that White likely plays inside some. Prior to last year Jennings played some on STs too.
I do agree that Jennings likely is eventually phased out, but hard for me to see it this year just with the numbers at the position. They'd save like $1M by cutting him after they backfill the roster spot, which is nothing. NEXT year, cap space is tigher overall and they save like $4M if he's cut so it's a little more material. I do expect him gone next year but I'd be surprised if it's this year.