ORCHARD PARK, N.Y. -- Philip Rivers has seen firsthand Melvin Gordon's maturation from workhorse, bruising running back at Wisconsin to a versatile, do-everything performer for the Los Angeles Chargers.

His three-touchdown performance in a 31-20 win over the Buffalo Bills at New Era Field on Sunday was evidence of that.

Gordon's ability to sniff the end zone is a continuation from last year. Since 2016, Gordon's total 27 touchdowns is second in the NFL only his crosstown rival Todd Gurley of the Los Angeles Rams (29).

Now in his fourth season, what has changed for Gordon is his effectiveness as a pass-catcher out of the backfield. Two of Gordon's three scores against the Bills were touchdown catches.

"He's at the point where he sees the running back as a three-down position, and also, who cares how you get the touches," Rivers said. "It's not a 25-carry, 150-yard league anymore. It's 16 carries and seven receptions -- how many touches does he get for 150?

"You see it around the league -- the best backs, that's what they do. He also has embraced that 'Shoot, I don't care if you're handing it to me, I'm going to run the heck out of a route and throw it to me.' ... At Wisconsin, it was handed to him and he ran through holes like this," said Rivers holding his hands out wide. "I think he's just grown as a pro."

Gordon's ability to get into the end zone has helped the Chargers particularly in the red zone. The Bolts were awful in the red zone last season, finishing No. 28 in the NFL at 46.8 percent red zone efficiency. But through two games this year, the Chargers are 5-of-6 in the red zone, and Gordon is responsible for three of those scores.

"They're just calling it up, and sometimes stuff has to happen for you," Gordon said. "And it's been going my way, so hopefully it stays that way."

Rivers said the difference for Gordon from his rookie season in 2015, when he failed to get into the end zone, to now is Gordon's play speed, pointing to Gordon's touchdown on a 9-yard out route.

"He had his play action, and he made sure he checked his protection, but he got it and separated in a hurry," Rivers said. "I was really getting ready to throw that to Tyrell [Williams], but then I was like, 'Oh, there's Melvin' mid-delivery. That was nice by him."

Through two games, Gordon leads the Chargers in receptions with 15 for 140 yards and two scores. If Gordon keeps up that pace, he would be the first running back to lead the Chargers in receptions since LaDainian Tomlinson accomplished that feat in 2003, finishing with 100 receptions for 725 receiving yards.

Moving forward, one thing to monitor for Gordon this week is what he described as an upper-body injury. Gordon suffered the injury early in the fourth quarter. Trainers evaluated him on the field before he walked off on his own.

Gordon has missed a total of just five games in four NFL seasons.

"I thought he played well," Chargers head coach Anthony Lynn said. "He got a little tired in the end. We got him out of the game to rest him up, but I thought he played well."