While Detroit cornerbacks Justin Coleman and Rashaan Melvin were rather busy in Arizona last week, targeted 13 and 11 times, respectively, Lions Pro Bowl cornerback Darius Slay was thrown at just four times. Cardinals quarterback Kyler Murray completed just one of those passes for six yards. That one completion came on a 3rd and 11 play. When targeting Slay, Murray had a passer rating of 39.6.

Slay is expected to have a much more difficult task this week against the Los Angeles Chargers and their terrific Pro Bowl duo of veteran quarterback Philip Rivers and wide receiver Keenan Allen.

"Very under-appreciated," Slay said of the 16-year veteran Rivers. "He did a lot for that city. Put the city on his back. You see it on film how much he fights and how much he competes at a high level. I look forward to always going up against quarterbacks like that."

Rivers, who'll be making his 210th consecutive start Sunday, became the first quarterback in league history to throw for 3,500 yards in 11 consecutive seasons last year. His favorite target the last two seasons has been Allen, who caught 102 passes in 2017 and 97 last year. Rivers and Allen have connected on 28 touchdowns over the last six seasons, and the two are off to a good start this season, hooking up eight times for 123 yards and a touchdown in last week's overtime win vs. Indianapolis.

That's where Slay steps in. It's likely he finds himself across from Allen at some point Sunday, and who knows, the Lions could elect to travel Slay on Allen all game, which they've done with the opponent's best receiver before.

"He's very difficult," head coach Matt Patricia said of Allen. "This guy is an unbelievable athlete, an unbelievable wide receiver. The thing about him that is unique is that he has great route-running ability. His ability to cut to release off of the line of scrimmage to really kind of move the defenders at the line to get open, get into space.

"His top of the route quickness -- he's got some subtleties in there. His head-turns, his shoulder-leans, and some of the ways he skips off the line of scrimmage. He has some unorthodox releases too that are just extremely difficult to defend against.

"You have to deal with all of that and then on top of that if you have good coverage, the quarterback has a lot of trust in him. He's going to put the ball up ... that's I think what makes those guys so difficult when you have a really good quarterback that trusts him to make those plays."

When the Lions opened the season in San Diego in 2015, Allen caught two passes with Slay in coverage for 21 yards and no touchdowns. Allen caught 15 passes total in that game, mostly on the other side with Rashean Mathis in coverage, for 166 yards.

Slay can probably expect to be more busy Sunday than he was last week in Arizona. He's got the most passes defended (90) in the NFL since 2013, and will be looking for a few more Sunday vs. Rivers, Allen and co.

STILL LEARNING

Linebacker Jarrad Davis is doing his best to get back on the field for the Lions' defense. Davis has been out since suffering an ankle injury Week 3 of the preseason.

Davis was sort of a player/coach on the sideline last week in Arizona after being listed as inactive due to the injury. He's obviously chomping at the bit to get back on the field, but Davis said being hurt has allowed him to take a step back and look at the big picture on defense. He's hoping it's made him a better player and teammate when he gets back.

"Being able to get a feel for how my guys think," Davis said. "How Jahlani (Tavai), how Christian (Jones), how DK (Devon Kennard) and Jalen (Reeves-Maybin), and how everyone thinks who is playing in that linebacker room.

"And then getting a feeling for what the d-line is seeing and the what the DB's are seeing. Not being out there gives me a chance to not only roam on game day, but in practice, I can roam on the sideline and say, 'Hey, what did you see right here? Why did you call this? Why did you check that? What were you thinking? What made you do that?' Just to be able to get a feel for what the other 10 guys are doing out there."

Davis said that's helped him better understand everyone's role in the defense and what he's trying to do within it, too.

As for getting back on the field, Davis is listed as questionable for Sunday.

BUILDING RAPPORT

Rookie tight end T.J. Hockenson wasn't the only 100-yard pass catcher for the Lions last week in Arizona. Veteran slot receiver Danny Amendola caught a team-high seven passes last week for 104 yards, including a 47-yard touchdown.

Often in training camp, during special teams periods, Stafford and Amendola would spend time working on one open end of the other field going through the route tree and working on timing. It's early, but if last week is any indication, Amendola could be becoming a trusted option for Stafford.

"We're growing and learning every day," Amendola said Friday. "I'm trying to formulate a role on this offense and trying to expand that role too and trying to make as many plays as I can to help the team win."

EXTRA POINT

• Left tackle Taylor Decker (back) didn't do much at the open portion of practice Friday and is listed as questionable for Sunday. Tyrell Crosby took first-team reps at left tackle during Friday's open session. Davis and Da'Shawn Hand (elbow) are also questionable. Cornerback Rashaan Melvin (knee) is good to go, which is good news for Detroit's secondary. Melvin played well last week opposite Slay.