Vic Fangio is testing the Eagles, looking to establish roles on his defense. There’s room to grow.

If preseason games are tests, the play calls Vic Fangio relays to his players are the questions. It’s up to the players to come up with the right answers as they execute their assignments within the calls.

In Thursday night’s preseason opener against the Cincinnati Bengals, Kelee Ringo didn’t have the right response when tasked with limiting Ja’Marr Chase on his eventual 36-yard catch-and-run touchdown.

Fangio had called Cover 0 — in which every defensive player is in man coverage or rushing the quarterback, leaving no safety help over top — to test his secondary. In a regular-season circumstance, it would be a dangerous call. Fangio didn’t call Cover 0 against the Bengals in Week 8 last season because of the threat posed by two-time Pro Bowl quarterback Joe Burrow and his top receiving duo in Chase and Tee Higgins against man coverage.

“There’s a lot of times in the preseason where you’re calling stuff for the purpose of evaluation,” Fangio said before practice on Saturday. “Whereas during the season, a real game, you’re calling stuff … anything that you can to help your guys.”

» READ MORE: Eagles’ second corner spot still up for grabs after Kelee Ringo and Adoree’ Jackson struggle vs. Bengals

The Cover 0 call was meant to stress all of the defensive backs, not just Ringo. But the 23-year-old cornerback was singled out on the play, as he took a bad angle in his failed attempt to tackle Chase.

“I’m not upset that the guy caught the ball on him,” Fangio said. “I’m upset that he didn’t tackle him. And he’s got to realize where he is on the field. Use the sideline. Realize who he’s going against. Those are all things you’ve got to process and factor in in a millisecond.

“And he didn’t do a good job of that on that play. But I expect him to learn from that. I expect him to improve from that.”

Ringo and Adoree’ Jackson, the top contenders for the starting outside cornerback job opposite Quinyon Mitchell, have plenty to learn in the aftermath of Thursday’s game. According to Pro Football Focus, Ringo conceded four receptions on four targets for a team-high 79 yards and a touchdown. As of Saturday afternoon, Ringo’s 79 receiving yards against was the second-worst total among cornerbacks in the first week of the preseason.

Jackson fared only slightly better. He allowed four completions on five targets for 45 yards (third-most on the team). Chase did the most damage against Ringo and Jackson, with 71 of his 77 receiving yards (and the touchdown) against them.

No, Ringo and Jackson weren’t playing with the majority of the Week 1 starters, aside from possibly Sydney Brown and Jeremiah Trotter Jr. Still, preseason games provide Fangio with valuable information about Ringo and Jackson as he works to identify the Eagles’ second starting outside cornerback, regardless of the caliber of teammates who compete alongside them.

“It all factors in,” Fangio said. “There’s not an overriding thing. Our practice against our team, we’ve got the Browns coming in here for a couple [practices], the three preseason games. It’s an accumulation.”

Thursday night was relatively quiet for the Eagles’ edge rushers.

The group, which did not include Nolan Smith or Jalyx Hunt, combined for three pressures. Joshua Uche, Patrick Johnson, and Antwaun Powell-Ryland, who each notched one pressure, per PFF, were the only Eagles edge rushers who hurried the quarterback.

Fangio is still looking for someone to separate themself among the depth edge rushers in the competition to make the initial 53-man roster.

“I think some of them are making good strides,” Fangio said. “I think Uche’s getting better. He’s just got to keep learning how we want to do all the little details. Both against the run and the pass. [Azeez] Ojulari, same. And then the other guys, we’re looking for somebody to surface to say, ‘Hey, maybe we need to keep this guy.’”

Throughout training camp — and in the first preseason game — most of the Eagles’ pass-rush juice has come from the interior. Moro Ojomo has been one of the stars of camp with his ability to break into the backfield. Jalen Carter, who has been participating in team drills for the past week since returning from his shoulder injury, had a strip-sack on Jalen Hurts in Saturday’s practice.

Defensive tackle Ty Robinson, whom Fangio said “has been coming along” in camp, was the only Eagles defender with a sack on Thursday. The fourth-round rookie out of Nebraska got home on a stunt executed in tandem with Gabe Hall, another defensive tackle contender for the initial 53.

Jihaad Campbell’s highly anticipated preseason debut had to wait until the second Bengals possession on Thursday.

Fangio initially planned on starting him, he said. But the team’s trainers were concerned about the rookie linebacker’s snap count, given that Campbell has only been practicing with the Eagles for the last few weeks since recovering from offseason shoulder surgery. Instead, Trotter and Smael Mondon were the inside linebacker duo on the opening drive.

“A day or two before the game, the trainers asked if we only play Jihaad much fewer snaps coming off [his injury],” Fangio said. “So it made sense to not start him so there would be a logical rest period for those other two guys.”

» READ MORE: What we learned from Eagles-Bengals: Jihaad Campbell flashes

Campbell played just 15 snaps in the preseason opener, the second-fewest among the defense. He was active in that brief span, though, and finished with three tackles.