Chicago Bears all-world pass-rusher Khalil Mack was placed on injured reserve Friday with a foot injury that will require season-ending surgery to repair. It’s the first time in Mack’s career that he’ll miss an extended stretch of games; he appeared in a stretch of 109 of 110 games with the Raiders and Bears. Now, there’s legitimate concern about what his future looks like in Chicago.

Mack’s injury has both short- and long-term consequences for the Bears. In the short term, Chicago has to figure out how to fill the pass-rush production Mack’s leaving behind. He has six sacks in seven games and the depth on the roster behind him doesn’t exactly inspire confidence.

Second-year pro, Trevis Gipson, has a great deal of upside, but he’s still more of a rotational player at this point in his career. Newly signed Bruce Irvin feels like a desperation play, while Cassius Marsh’s biggest moment of 2021 was the controversial taunting penalty he received in Week 9—it’s likely to be his only ‘big’ moment this year. Robert Quinn will assume the role as Chicago’s premier pass-rusher for the rest of the season but if he doesn’t get help from his running mates, his production could experience a very sharp decline. He’s been more of a complementary player to Mack than a standalone star.

Looking forward, Mack’s injury calls into question whether his best years are in the rearview mirror. His contract makes it nearly impossible for the Bears to move on from him in 2022, as he’d cost Chicago $24 million against the salary cap next season before dropping to less than half of that in 2023. It’s more likely the Bears will reach their ‘Mack crossroads’ two seasons from now, which isn’t necessarily bad news. Mack will have nearly half of this season and the entire offseason to get his body right for what will be a critically important 2022 campaign at this point in his career. He turns 31 years old in February, and while that certainly isn’t ancient for pass rushers, it isn’t young, either.

Had the Bears been in the midst of a playoff run and charging for an NFC North title this year, Mack’s injury would be the kind of devastating turn of events that derail seasons. Instead, at 3-6, there’s little to no hope Chicago will be in the postseason, which makes Mack’s injury induce nothing more than a shoulder shrug and a ‘better luck next year’ reaction. It’s a sad state of affairs for a team that feels like it’s wasted a Hall of Famer’s prime seasons.

General manager Ryan Pace pulled off one of the biggest trades in recent NFL history on Sept. 1, 2018, when he sent the Raiders a boatload of draft picks, including first-rounders in 2019 and 2020, a sixth-rounder in 2019, and a third-rounder in 2020, for Mack. The Bears received a 2020 second-rounder from the Raiders in addition to Mack, which Pace flipped into tight end Cole Kmet. It was a trade that sparked excitement, enthusiasm, and most of all, hope, among Bears fans. But it was a deal that occurred at an odd time in Chicago’s roster construction considering the team was fresh off a 5-11 season in 2017. Were they really a player like Mack away from making a Super Bowl run?

In 2018, the answer appeared to be yes. With Mack’s 12.5 sacks leading the charge, the Bears defense was among the most dominant in the NFL and supercharged Chicago to a 12-4 record, an NFC North crown, and a home playoff game. But for Cody Parkey’s double-doink disaster, the Bears may have a playoff victory from that season on their ledger, too. We soon learned, however, that the 2018 season wasn’t a fair reflection of where the Bears were in their rebuilding timeline. Remember: Mitch Trubisky was still raw and finishing just his first full season as the team’s starting quarterback. He had a long way to go and he failed to develop—at all—during his Bears tenure. As a result, the entire team stalled.

The Bears regressed to 8-8 in 2019 and 2020, and while they did back into the playoffs last year, their postseason game felt like a 60-minute delay of the inevitable.

That makes it three-and-a-half seasons Mack has been with the Bears. Chicago has a 31-26 record since trading for him, but if we eliminate the 2018 season (which feels like an outlier at this point), they’re 19-24. That feels about right, to be honest. And it’s a shame.

Mack is the kind of difference-maker who can take a team that’s close to a championship over the top, much like the Los Angeles Rams are trying to do with their trade for Von Miller. It’s a trade that makes sense. The Rams are an obvious contender in the NFC and they truly could be just one player away. A guy like Miller, whose resume of pass-rush production is on par with Mack’s, is the type of dude who can push them over the edge. Were the Bears ever that close? Did Pace think following a 5-11 season with a rookie quarterback and in Year 1 with a new head coach that they were close enough to competing for a championship that adding Mack would make sense? It’s hard to believe he did.

Instead, Pace approached the Mack trade like anyone in his position would’ve. The opportunity to land a player with generational ability doesn’t come along often—if ever. You have to take your best swing to acquire a talent like that and Pace connected on a walk-off home run. Sure, maybe the Bears weren’t ready to win it all, but adding Mack certainly got them closer. Let’s face it: they haven’t had a losing season since he’s arrived.

But it still feels like Mack’s window of high-end production is beginning to close, and the Bears may run out of time to take full advantage of his ability because of their failures on offense, the blunders by the coaching staff, and the years of unwarranted confidence placed in Trubisky. If Mack begins breaking down and his production slows, the blame will rest with Nagy and Pace for not winning more games with a player like Mack on the roster.

Life without Mack—or, at least a look at what that life could be like without him—kicks off against the Baltimore Ravens and Lamar Jackson in Week 11. It wouldn’t be an easy task with a healthy Mack on the field. Now, it’s a near-impossible challenge for a defense that, like Mack, no longer possesses the bite it once did.