Three weeks ago, the national narrative was that the Boston Celtics’ season was ruined in the wake of the gruesome ankle injury suffered by one-time Butler star Gordon Hayward in the season opener.

The Celtics dropped that game and the next. Thus, it would be clear sailing for the Cavaliers to the NBA Finals for a rematch with the Golden State Warriors.

At the time, I wrote that perhaps a relatively unknown rookie would emerge to replace Hayward.

Since then, the Celtics have won 12 straight and have the best record in the NBA (the Cavs are 6-7) on the strength of the play of veterans Kyrie Irving (20.3 ppg) and Al Horford (14.6 ppg), second year pro Jaylen Brown, (14.5 ppg) and rookie Jayson Tatum (13.7 ppg).

Unfortunately, though, Irving was removed from Friday’s game for a possible concussion along with a facial injury that turned out to be a “minor” fracture. At least Horford was able to return on Sunday after suffering a concussion of his own eight days ago.

A prolonged absence by Irving may be too much for the Celtics to overcome, and that has been the reaction of the mainstream media: the Celtics overcoming injuries, no particular concern about concussion in the NBA.

Two weeks ago, ESPN had the nation on high alert that Bears tight end Zach Miller was in imminent danger of losing his leg in the wake of the knee dislocation he suffered two days before. Yes, there was a risk of amputation but it wasn’t that great. The surgery Miller needed and received in a timely manner to repair an artery is successful 90 percent of the time. A week ago, he returned home.

Miller’s career is at far greater risk than his leg was. He faces further surgery to reconstruct and/or repair the knee. The three high school soccer players with this injury, whom I have treated during my career, all returned to play a year later. One even went on to play in college. However, at age 33, Miller does not have youth on his side.

A week ago, I reported on the progress the Ivy League has made in reducing the incidence of concussion in the wake of the conference moving kickoffs up from the 35-yard line to the 40.

By Thursday, the supposedly highest level of the game, the NFL, demonstrated once again that it is unable to stay out of its own way.

That afternoon, the league took public relations beatings in Baltimore from Bob Costas and in Boston from neuropathologist Dr. Ann McKee regarding CTE. The league’s response? Dead silence.

That evening, there was a game played between the Seahawks and Cardinals, and despite winning, for Seattle, the game was a disaster.

If they’re looking for anybody to blame, Pete Carroll and staff need only look in the mirror. All-world cornerback Richard Sherman tore his right Achilles tendon. Yet, the team knew the tendon was strained days before the game was played. But playing Sherman was not misstep enough. When quarterback Russell Wilson was sent off by the referee after taking a hard hit to the chin, a team physician and independent neurological expert, in direct violation of NFL rules, did not examine him.

In the wake of that lapse, surely no team would repeat the behavior on Sunday. However, that is precisely what the Colts did with fill-in quarterback Jacoby Brissett — while should-be starter Andrew Luck was finding it necessary to seek treatment in Europe for his ailing shoulder.

John Doherty is licensed athletic trainer and physical therapist. This column reflects solely his opinion. Reach him at Follow him on Twitter @JDohertyATCPT.