There are still a few days to go until the Chargers open up their season against the Chiefs and they're already Chargers-ing. Having already lost tight end Hunter Henry and cornerback Jason Verrett for the season, the Chargers are suddenly dealing with an injury to arguably their best defensive player that'll prevent him from taking the field in Week 1 and maybe beyond.

On Friday, the Chargers announced that defensive end Joey Bosa will not play against the Chiefs on Sunday. The announcement came an hour or so after Bosa was spotted wearing a walking boot. According to Chargers coach Anthony Lynn, Bosa is "week-to-week."

As Jack Wang of The Orange Country Register explained, Bosa originally hurt his left foot in early August, which is why he missed the preseason. The injury eventually healed, but Bosa suffered a new injury to the same foot on Wednesday.

The Chargers are now looking at the possibility of beginning the first few weeks of the season without a pass rusher who's notched 23 sacks since entering the NFL in 2016. Only three players have more sacks in that span.The Chargers still have Melvin Ingram to rush the passer, but what made their front-seven so special was the presence of two elite pass rushers. They'll be reduced to only one against the Chiefs, who are starting 2017 first-round pick Patrick Mahomes at quarterback after he spent nearly his entire rookie season watching Alex Smith direct one of the league's best offenses.

Trusting Mahomes against the Chargers' defense was always risky, but it's easier to believe in him now that Bosa won't be harassing him all game long. It's also easier to believe in the Chiefs' chances to beat the Chargers on the road. It might be Week 1, but it's still a hugely important game between the two presumed frontrunners in the AFC West.

The larger concern for the Chargers is that they could be without Bosa for more than just one week. After facing the Chiefs, the Chargers head to Buffalo before playing the Rams, 49ers, and Raiders.