Here’s the thing about injuries...they suck.

When Andrew Luck stood at the podium Saturday night to retire from football at age 29 - earlier than expected, sooner than planned - the Indianapolis Colts’ franchise quarterback did an extremely difficult but brave thing.

He left a sport he loved because he didn’t love it enough anymore.

“For the last four years I’ve been in this cycle of injury, pain, rehab. And it’s been unceasing and unrelenting, both in season and off season. And I’ve felt stuck in it. And the only way I see out is to no longer play football.”

Colts fans were livid, many booing him off the field since the news broke midway through the team’s third preseason game.

It’s impossible not to sympathize with their visceral if not inappropriate reaction - a feeling of betrayal by the man they’ve been hoping would deliver them to the Promised Land for the past seven seasons.

Don’t get me wrong. I didn’t/don’t condone the booing, but I understand the emotion.

I mean, imagine if John Elway retired in August 1997, two weeks before our revenge season that truly turned out to be the best Broncos’ season in franchise history (ok, I’m biased, but no fan would disagree that was a magical season)? Or what if Peyton Manning hung it up in the fall of 2013 or 2015 - months after we had made plans for the comeback season and too late to find a decent replacement? (we haven’t found a decent replacement yet even with months/years notice).

The collective shock from both fans and the sports media hints at a larger societal issue where we believe that “playing through injuries” is just part of the game.

A New York Times opinion piece highlighted the incongruency that exists between the mentality of many of today’s younger athletes who are concerned with their future health and that of an older, more traditional sports culture that wholeheartedly believes “rubbing some dirt on it” should be enough.

This partly explains the collective gasp you heard from the sports world when the superstar quarterback Andrew Luck announced last weekend that he was retiring from the Indianapolis Colts. What really shocked those booing fans and the dumbstruck media, though, was that Luck had violated the cardinal norm of sports culture — playing through the pain — after a career of fidelity to it.

...But our shock at a player’s willingness to opt for self-preservation over inevitable bodily immolation shows how deeply rooted that toxic masculinity remains.

For fans and sports reporters to “not get it” is perhaps not fair to Andrew Luck - yet it is certainly forgivable. They love their quarterback and they felt abandoned by him in the ninth hour. They’ll move on and eventually come to view Luck’s decision as smart and brave, even if they still hate it.

But for former players, such as Steve Beuerlein or Brandon Stokley, to berate a player who has suffered injury after injury in his prime years - from shoulder dislocation to an AC joint sprain to a kidney laceration to finally an ankle injury this preseason - is just insensitive and stupid.

Because here’s the thing about injuries.

They suck.

And the pain suffered during rehab is nothing compared to the mental anguish involved during recovery - especially after multiple injuries and multiple rehabs.

Just ask Jake Butt, who has suffered three torn ACLs since entering the NFL two years ago and has played only three regular season games - and may not see the field another season due to complications from the latest knee injury and a scheduled “clean-up surgery.”

Butt told The Athletic back in early August that rehab “nearly broke” him a couple of times.

“I got a Bible study with my buddies back in high school and I just leaned on them,” he said. “When it happened originally, I called them and we were on the phone for three hours and I don’t think I said a word. I just cried and listen to them try to breathe life into me.

“Injuries are a part of this league, but they’re tough. They’re something you have to deal with and you better have a good support system around there to help you get through it.”

Butt is likely going to need that support system again as his football future is in up in the air. So it’s not surprising he could empathize with Luck:

Although Butt caught two passes against the Rams last weekend, the third-year tight end experienced soreness and was held out of practice all week.

Butt won’t play in the final preseason game tonight and that could signal he will not be included in the final 53-piece puzzle.

So when Beuerlein says there is “no scenario” where Luck’s decision is defensible or when Stokley says “it’s just football, you’re always going to be hurt,” these are just hot takes to trump all hot takes.

Sports psychologists will tell you that one of the most challenging hurdles for any athlete in any sport has nothing to do with improving or competing.

It is staying positive during rehab from an injury. For many athletes, involvement in their sport is directly tied to their self-esteem and validation in life, so suddenly having that taken away takes a far greater mental toll than outsiders realize.

I can attest to this because I’ve been there - on a much smaller stage - but anyone who has come back from an injury at any level understands the challenge.

Three out of my four collegiate gymnastics seasons ended with an injury that kept me out of the final conference championship meet and postseason competitions. Every offseason was spent in the training room with grueling physical therapy, agonizing minutes in an ice tub, and way-too-long-and-boring workouts on a stationery bike instead of in the gym.

Staying mentally focused on getting better and not second-guessing a decision to stay in the sport was taxing. Being able to “take it one day at a time” and push physically but not get down mentally was exhausting. Not being afraid to go 100 percent and risk injury again was a damn near-heroic feat.

A recent case study of several elite athletes during their injury recovery (written by my awesome sister, a credentialed sports counselor who works with athletes on the mental side of sport) showed that the overwhelming emotions were “anger,” “frustration,” “anxiety” and “depression,” and the mental fatigue associated with those was immense.

Butt is still hanging in there, focusing on his will to win more than on the long and familiar roller coaster ahead.

“I will continue to do everything in my power to play this year and feel extremely confident that I will,” Butt said via Twitter. “These injuries have taught me so much. Failure, setbacks, and tough times have shown me my absolute drive and will to win.”

Fighting back from injury with a resolve to play again is praiseworthy and nothing short of remarkable when accomplished.

Walking away from a sport because you realize you can no longer put up that fight is equally praiseworthy and nothing short of courageous.