If he signs on, Jon Bernthal will play Jon Teague, an LAPD cop who is in the middle of his department's ongoing war with gangster Mickey Cohen in the 1940s and 1950s. Frank Darabont wrote the pilot script based on John Buntin's non-fiction book of the same name.
It isn't known how this will affect Jon Bernthal's status on the hit AMC series The Walking Dead. Frank Darabont created the popular AMC series, but departed as showrunner after Season 1. It is possible Jon Bernthal could star in both shows, if the L.A. Noir pilot is picked up to series, and doesn't conflict with The Walking Dead's shooting schedule.
However, there were rumors that Jon Bernthal asked to be let out of his contract on The Walking Dead soon after Frank Darabont's departure. Jon Bernthal's character, Shane, was killed off in the Robert Kirkman graphic novels upon which the AMC series is based, so it's possible that the show may follow suit sometime in Season 2.