COSTA MESA, Calif. -- Los Angeles Chargers defensive end Isaac Rochell had the tough task over the weekend. He tried to replace one of the best defensive players in the game in Joey Bosa.

A seventh-round selection in last year’s draft out of Notre Dame, Rochell finished with four tackles and no sacks in a 38-28 season-opening loss against the Kansas City Chiefs on Sunday.

Without Bosa in the game for the Chiefs to focus on, his counterpart Melvin Ingram recorded three quarterback hits but no sacks.

The Chargers had one sack of elusive quarterback Patrick Mahomes. Ingram had a couple of near misses, but with Bosa week-to-week and headed for a second opinion on his bruised left foot Wednesday, the Chargers need to devise a plan to replace Bosa’s production.

Bosa is scheduled to meet with renowned foot specialist Dr. Robert Anderson, sources told ESPN Insider Adam Schefter. Bosa would like to determine the extent of his left foot injury and get a timetable for his possible return. Per Schefter, Bosa’s first MRI last month revealed a soft-tissue injury between the first and second metatarsals.

“I thought Melvin had a good day rushing off the edge, applying some pressure,” Chargers coach Anthony Lynn said. “He didn’t get there all the time, but he was pretty close. He is going to get more attention now that Joey isn’t out there, so Isaac is going to have to step up and really play his role. Isaac was solid, but I think he can play better.”

According to ESPN Stats & Information research, since Bosa joined the Chargers in 2016, they have allowed 8.2 more points per game in the five games he missed. The Chargers are 13-15 in games where Bosa has played, and 1-4 in games where he has not played. The Chargers have a 6.6 percent sack percentage with Bosa in the game, and it's 4.7 when he doesn’t play.

The Chargers get some help from the schedule by facing the Buffalo Bills and, potentially, quarterback Nathan Peterman on Sunday. The Chargers finished with five interceptions in the first half against Peterman last year in Los Angeles during a 54-24 win. However, Bosa had pressures on four of those picks, so his impact likely will be missed.

Admittedly, stopping Chiefs receiver Tyreek Hill was the Chargers' biggest issue over the weekend. Hill finished with seven receptions for 169 yards and 2 touchdowns, along with a 91-yard punt return for a score.

But generating a more-consistent pass rush will be a goal against the Bills.

“Whoever is out there, if we can get some pressure, and if we can hold up longer in the back end to allow them to get there, that would definitely help,” Chargers cornerback Casey Hayward said. “Pass rush and coverage work together, so if we can do that for each other, it would definitely be a better day for us.”

One player who could help fill the void of Bosa’s absence is this year’s second-round pick for the Chargers, outside linebacker Uchenna Nwosu. Nwosu totaled 10 combined tackles and 3 sacks during preseason play, but he played in only two defensive snaps against the Chiefs in Week 1.

Lynn said part of the reason Nwosu didn’t play against the Chiefs is because the USC product had not had many reps at Bosa’s position.

“I hate to put a guy in a position that he hasn’t played all year,” Lynn said. “He has been an outside linebacker and comes in sometimes to back up Melvin at the Leo spot, but as opposed to the big end, he hasn’t played one down of that. That’s part of why you didn’t see him in there that much.”