The first thing about Martin that pops out is his size. He is 6’3, 240 lbs, which is great size for a NFL linebacker. He has good straight-line speed, which will help fill the in the run game, and on special teams.
Martin missed quite a bit of time at Minnesota with various injuries. He struggles in coverage, and has poor technique that leads to missed tackles. He played a few different positions at Minnesota, which many scouts think actually hurt his development. That could have led to his inability to quickly diagnose developing plays.
The bottom line is Martin’s role in 2020 will be special teams. His size and straight-line speed are a plus, but he’s going to need a lot of coaching and technique development to play meaningful snaps on defense.