Yeah he had a fairly typical for him role in Concussion. Will Smith as a Nigerian pathologist was something of a revelation.
Is the film any good? I can imagine it being an interesting topic for a documentary especially as there are a number of contact sports with similar issues, but it seems odd as a movie subject. Ridley Scott directing Will Smith and Alec Baldwin. I'd never heard of it until your post and it certainly never reached the Dome Cinema in Worthing, or any of the multiplexes nearby.
The film direction was sort of good in a formulaic way, there were some outstanding performances though. It ended rather abruptly just as the main protagonist faced his biggest challenges.