In the mid-2000s, the “Monday Night Countdown” pregame show on ESPN featured a segment called “Jacked Up,” celebrating the most vicious hits of the week.

Former Denver Broncos great Tom Jackson would set up each play with some jokey commentary, and as ESPN showed multiple replays of a collision that almost always left one player on the ground, writhing in pain, Jackson would say, “He got …”

“JACKED UP!” came the uproarious response from host Chris Berman and a couple of other former NFL players. They didn’t even try to contain their laughter and glee.

A lot has changed since then. Most of the hits celebrated on “Jacked Up!” would result in 15-yard penalties and possible fines. The NFL has a “concussion protocol” for medical monitoring of players who “got their bell rung” or “got dinged up,” as coaches and announcers would phrase it back in the day.

Did the NFL suddenly develop a conscience about the exceedingly violent nature of its multi-billion-dollar game? Please.

Writer-director Peter Landesman’s “Concussion” is a sobering, sometimes infuriating look at one doctor’s discovery of chronic traumatic encephalopathy (CTE), and his crusade to tell the country its favored game was causing the deaths of many a former hero.

In one of the most devastating and heartbreaking supporting performances of the year, David Morse is unforgettable as Mike Webster, the Hall of Fame center on the vaunted Pittsburgh Steelers Super Bowl teams of the 1970s.

Considered by many to be the best center in NFL history, “Iron Mike” was a god in Pittsburgh — but a dozen years after his retirement, he had become a delusional, self-mutilating, drug-addicted wild man, living in his pickup truck and barging around like a wounded bear.

When Webster dies at the age of 50, Dr. Bennet Omalu (Will Smith), a Nigerian-born pathologist with more than a half-dozen degrees, is assigned the autopsy.

(The first time one hears Smith’s Nigerian accent, it rings a little thin. But as the story evolves and we get to know Bennet and his eccentric genius and unbridled passion for his work, the performance is about so much more than the accent. This is one of Smith’s best performances. He’s playing a hero who knows being a hero usually means a lot of people are going to hate you.)

Conventional wisdom at the time held that former football players who died in their 40s or 50s suffered from dementia or early onset Alzheimer’s. The job of the team doctor was to get players back on the field. The job of the players was to stay on the field at all costs. The job of the fans (and usually the media) was the worship of football as a religion. Nobody was asking questions about the statistical impossibility that so many men with a common profession involving extreme physical trauma were stricken with “early onset Alzheimer’s.”

Dr. Bennet Omalu starts to ask those questions. By his estimation, since childhood and through college and 18 professional seasons, Webster had sustained at least 70,000 violent blows to the head. By the time Webster was 50, he had lost his mind.

In Bennet’s estimation, that means football killed Mike Webster.

“Concussion” morphs into something of a scientific-sports thriller, with Bennet uncovering more cases of CTE while the NFL and myriad medical experts refute his claims. Along the way, Bennet marries the beautiful, smart and strong Prema (Gugu Mbatha-Raw), who gives at least three “Don’t give up now!” speeches to her husband. (This is NOT a subtle film. When the phone rings, carrying with it the potential for another hate call, the lighting is overly dramatic, and Bennet and Prema look at each other as if they’re in the middle of a slasher film. Another scene in which a pregnant Prema frantically tries to elude a car tailing her is way over the top.)

Alec Baldwin is superb as a former NFL team doctor who spent years on the sidelines, giving injured players the OK to return to the field, and is now aching with remorse. Albert Brooks is pure gold as Bennet’s boss and mentor.

In a small but memorable role that will hit close to home for Bears fans, Adewale Akinnuoye-Agbaje plays Dave Duerson, the Notre Dame great who went on to star for the Super Bowl champs of 1985.

Like Mike Webster, Duerson died at 50. He shot himself in the chest after texting his family saying he wanted his brain to be donated to research — research that confirmed he suffered from CTE.

“Concussion” is a good movie that could have been great without trying so hard to be great. There’s more than enough high-level tension and drama in the story of our love for football and our celebration of its violent poetry — and the destruction it wreaks on some of its greatest warriors. When the film delves deep into Bennet’s fight to be heard, it’s riveting.

But then we get another melodramatic domestic moment, or another speech about what it means to be an American, how Bennet is going after the great American game, why Bennet could be an American hero, etc., etc. In the world of “Concussion,” people talk about being Americans practically every day of their lives. It’s overkill.

Still. This is a gutsy film in which the monolithic NFL is the chief villain. All the rule changes and concussion protocols in the world can’t change the reality that football is a violent game, played by men who are so much bigger and stronger and faster than the players of even 25 years ago.

ESPN no longer celebrates the most crunching hits of the week by chortling about men getting “jacked up!” but the NFL is bigger than ever. (Steve Young, one of the participants in “Jacked Up! — which was curious enough, given the seventh concussion Young as a player suffered ended his career — now gives interviews in which he expresses great concern about the toll the game takes on players.)

Today, when someone suffers a concussion, he’s taken out of the game and precautions are taken.

In the meantime, someone else has taken his place and is gonna do everything he can to jack up the man opposite him.

[s3r star=3/4]

Columbia Pictures presents a film written and directed by Peter Landesman. Running time: 123 minutes. Rated PG-13 (for thematic material including some disturbing images, and language). Opens Friday at local theaters.