Jaheim Bell, with measurements of 6'2" and 239 lbs at the Senior Bowl, is undersized for the position, having the height of a wide receiver and the weight of a slightly light tight end. He possesses average power and good acceleration but lacks elite speed, even for consistently attacking the third level (long). However, he manages to develop good quickness in short spaces thanks to decent footwork for his size. His agility and body control are also fairly good.

He has taken snaps in various positions, mainly as a slot, occasionally out wide, but also in-line and in the backfield. Primarily lined up in the slot due to his receiver-like TE profile, Bell has decent athleticism to create separation. His use of arms is adequate, and his in or out breaks are not sharp, making Jaheim a smooth runner.

He doesn't have a developed route tree; he has consistently run the same Dig, Go routes, or curls, and a few crosses. Bell is not a precise route runner and has a poor understanding of the game and what the defense offers. He struggles to adapt his route or settle down to provide a viable option for his QB against zone coverage, often finding himself amidst defenders, which is the worst situation for his QB.

He has the capability to attack the first two levels (short and intermediate) but not consistently. His athletic qualities do not always stand out, and his lack of IQ and separation pose problems.

Bell has a decent track of the ball and an acceptable catch radius but is far too prone to drops. His reactions are poor, his hand technique is weak, and he is not capable of making acrobatic catches. In traffic, he struggles in some games, and his transition from receiver to runner is not smooth. He often thinks about running with the ball before securing the catch.
With the ball in his hands, he is a decent threat without being capable of real big plays unless he has space ahead to make a move.

It's hard to see him winning reps against IDLs; his lack of power and weight is problematic. Moreover, he doesn't have good leverage technique or hand placement He alternates between good and less good against edges; I've seen good reps thanks to good lateral agility but also seen him completely miss because technically and in terms of power, he was outmatched.
In the slot, when blocking against safeties, he has the physical advantage but can be surprised by the power of some quality DBs. His angle taking on the move is mostly very poor, and he has cost his team the possibility of big plays or first downs quite often.

Jaheim Bell fits this seldom sought-after NFL profile of an undersized TE, plus the fact that he's not an elite athlete and his ball skills are very average doesn't help foresee any possible progression after 3 seasons as a starter.
I assess Jaheim Bell at best as a late Day 3 prospect.