When it comes to juggling snap counts, situational substitutions and old-fashioned gut instincts, no NFL assistant has a tougher job on game day than a defensive line coach.

“I pretty much go into the game with an idea of how I’m going to flow the rotation for the first three quarters,” Vikings defensive line coach Andre Patterson said. “And then once it gets to the fourth quarter, I’ll ride the hot hand.”

Sunday morning, roughly 30 minutes before the Vikings had to submit their seven gameday inactives, Patterson was told end Everson Griffen, his snap-count leader at the time, was too sick to play against the Chiefs.

The Vikings have nine defensive linemen. Eight normally are active on game day. But Griffen’s absence meant only seven would be active because end Justin Trattou remains on the roster despite a foot injury that has limited him to six snaps in Week 2.

Suddenly, rookie third-round draft pick Danielle Hunter was tabbed to make his starting debut. He had played only five snaps in the previous game and been active for only two games.

Patterson’s challenges didn’t end there. In the third quarter, backup defensive tackle Shamar Stephen was carted to the locker room because of a season-ending toe injury. That left Patterson with three defensive tackles, three ends and the probability of a seriously gassed D-line if one more body fell.

It helped that the Chiefs offense ran only 62 plays while failing nearly 80 percent of the time on third and fourth down. Only Denver has run fewer (61) against the Vikings this season.

Snap counts are a bigger deal than many people realize. Former Vikings guard Charlie Johnson used to say he could tell by how his knees felt the next four days whether the Vikings ran an inordinate number of snaps in a game.

Unlike defensive linemen, the goal for offensive linemen typically is to settle in next to each other in August and then play every snap until the season is over. The Vikings lost two preferred starters from their O-line in the preseason, but the current five have played all 325 offensive snaps together.

“It’s just the nature of the game and the fact offensive linemen are tough,” right guard Mike Harris said. “We have to be able to push through our fatigue. That’s mental toughness to be able to play every snap.”

Defensive end Scott Crichton plays primarily backup left end but can also move to tackle in the team’s sub packages. He has played only 24.7 percent (86) of the team’s 348 defensive snaps and sees advantages and disadvantages to going against offensive linemen who typically leave the field only when injured.

“I feel like I get a fresh burst coming in against a guy who has played the whole game,” he said. “But it’s also hard to get a rush in when you’re just standing on the sideline and you’re still kind of stiff from not playing.”

On gamedays, Patterson is on the sideline while assistant defensive line coach Robert Rodriguez is up in the coaches’ box. Rodriguez’s duties include keeping track of each lineman’s snap count.

Through five games, Brian Robison leads the defensive line with 287 snaps (82.5 percent). Griffen is second at 251 (72.1), followed by Sharrif Floyd (226/64.9), Linval Joseph (205/58.9), Tom Johnson (187/53.7), Crichton, Hunter (75/21.6), Stephen (67/19.3) and Trattou (6/1.7). Stephen will now be replaced by former Giant and Jet Kenrick Ellis, a fifth-year player who was signed Tuesday.

“It’s a good mix,” Griffen said a couple weeks ago. “I don’t know the rotation before the game, but I know I’m going to get the majority of the snaps. So I play with the same mindset every play until I get subbed out. And if you’re tired, you can pull yourself out. It’s all about being smart and not being selfish.”

Although the Chiefs didn’t heavily tax the defensive line in terms of snap counts, the game still was a testament to the depth of that particular unit. The Vikings controlled the line of scrimmage with five players playing at least 68 percent of the snaps.

The oldest guy, Robison, 32, played 54 of 62 snaps. And the youngest guy, Hunter, 20, doubled his season total with 50 snaps during a standout debut. Meanwhile, Floyd, who was exceptional, and Joseph, who was a steady force, each played 42 snaps.

“We have a system of how we want to do it,” Patterson said. “And there’s also a feeling based on the situation in the game. At times, even though [snap counts] are high, I got to ride the horses that brought me there.”