Will Smith is no longer the world's biggest movie star. Over the past few years, the once universally beloved showbiz hyphenate has undoubtedly seen his Q Score fall, tarnished by his push to turn his son into his successor and by all the weird coverage his children and marriage have drawn. He no longer raps, he hasn't been on TV in nearly two decades, and no matter how he tries to spin it, he can't make the public understand and forgive his decision not to fill the title role of Quentin Tarantino's Django Unchained. After a decade and a half of headlining almost exclusively blockbusters, Smith's few recent projects have either underperformed or outright tanked. Even a can't-miss project like Men in Black 3 needed international moviegoers to turn profit despite favorable reviews.

Smith sets aside stardom concerns to do some good old-fashioned acting in Concussion, a true drama about Bennet Omalu, the Nigerian forensic pathologist who discovered a link between head trauma and brain abnormalities by examining the remains of deceased former NFL players. The film is timely and topical. It's also important, as evidenced by its Christmas Day opening across from huge tentpoles and expanding awards hopefuls.

Concussion takes its time to develop its hero: a highly educated, slightly eccentric immigrant who takes great pride in performing meticulous autopsies at a Pittsburgh hospital. Certain colleagues (Mike O'Malley) question his methods, but Omalu is respected by many, including his mentor, Cyril Wecht (Albert Brooks). The thrifty, hardworking Omalu is unfamiliar with the famous decedent he is assigned in 2002 when beloved former Steelers center Mike Webster (David Morse) passes away at age 50, a tormented, derelict victim of self-abuse. Omalu orders all kinds of irregular tests as part of his post-mortem of the NFL alum, paying for the procedures out of pocket. It is this case which gets the doctor to discover what others have missed, leading him to diagnose a condition he helps name chronic traumatic encephalopathy (CTE for short).

Investigations of other NFL athletes whose lives have ended prematurely amidst mental instability support Omalu's findings, to the interest of the scientific community and the absolute horror of the National Football League. The NFL is the villain of this film and its unwillingness to accept Omalu's work is likened to to Big Tobacco's absurd, long-maintained denials of the link between smoking and lung cancer.

As the NFL's questionably qualified experts poke holes in Omalu's research, he finds an ally in one former NFL doctor (Alec Baldwin). Meanwhile, Omalu's supportive boss is suspiciously investigated by the FBI over petty charges of fraud.

Adapted from Jeanne Marie Laskas' 2009 GQ article "Game Brain" and directed by Peter Landesman (who wrote 2014's nonstarter Kill the Messenger), Concussion is neither conventional biopic nor obvious Oscar bait. It is a film that basically attempts to do for this controversial subject what Spotlight does for the Catholic Church's concurrent sex abuse scandal. It is, however, not nearly as successful or moving as that presumed Best Picture frontrunner.

Landesman does draw a number of strong performances from the cast, including Smith, doing more acting than he perhaps ever has before (confession: I still need to see Ali and Six Degrees of Separation). But the story is not presented as cleanly or compellingly. And the subject never seems to bear anywhere near as much importance as the film indicates, not even with its empathetic portrayals of down on their luck retired athletes and cautionary looks at at-risk adolescents.

Furthermore, the conspiracy vibe never is as believable and threatening as the movie wants it to be, even if no one doubts the power and resources of the National Football League, which is amusingly said to have ownership of the first day of the week.

Concussion attempts to humanize Omalu and manages to do so to a modest degree. Even if his marriage to a young Kenyan immigrant (Gugu Mbatha-Raw), whose footing he helps find by letting her stay at his place on his priest's request, never seems fully realized, it at least reminds us that this is a real person with a life beyond comforting and cutting up cadavers and taking on the NFL. If anything, the film could use more reminders of that humanity instead of painting Omalu as this flawless hero willing to stand up for what he believes in and not at all motivated by the personal advancement that comes with the turf.

Despite its timing and timeliness, Concussion probably won't earn much more than Smith's Golden Globe nomination for Best Actor in a Drama. It is a slightly above average picture with decent dramatic value. But that's not really enough to distinguish it at this time, when it is sharing multiplexes with better-made dramas and Star Wars.