It doesn’t take much to recognize Keenan Allen. Not only was he the only one of the Chargers’ receivers lined up wearing long blue sleeves last weekend, but he was also one of the sharpest route runners. He glides on the field. Creased at the elbows, his arms sway back and forth at his sides in a perfectly straight motion. His shoulders are squared and his chest is high. His feet are active and keep him running in a straight line. It’s like he’s pacing on a treadmill. And then he makes a quick break and you quickly realize that this is not just a workout, this is how he runs routes.

Allen is already one of the better young receivers in the league. He’s only a rookie, having recently turned 21 years old after leaving the University of California and falling to the third round of the 2013 NFL draft because of a reported failed drug test and a knee injury. Whatever the reason for the former, be it maturity or otherwise, it’s in the past. He’s clearly stepped his game up since being drafted after a sloppy set of OTA sessions earlier this summer.

“I think it became more serious for him,” Chargers offensive coordinator Ken Whisenhunt said. “I think he realized the way he was going wasn’t going to get him playing time. A lot of that is the leadership you see at that position, guys who are serious about the position. Danario (Alexander), Malcom (Floyd), Vincent (Brown), Eddie (Royal) — those are serious guys. You look at that and say, ‘I’ve got to change something about the way I’m doing it.’

Reports suggested that Allen’s route-running improved tremendously since the summer. He was always a good at that, though, eerily reminiscent of Miles Austin before the leg injuries. Allen shredded college cornerbacks at all levels of the field, leaving them at the line or well off the top of his break. In the NFL, it hasn’t been any different; just ask the Redskins’ cornerbacks, such as veteran DeAngelo Hall and rookie David Amerson.

They had the assignment of covering Allen the majority of Week 9, which proved to be difficult. Allen posted eight receptions on 11 targets, with 122 yards and one touchdown. He also put on a route-running clinic, easily separating from tight coverage and finding holes all over the field, especially the middle.

One of his finest routes came when he didn’t get the ball, however. It was nearly halfway through the second quarter when he was lined up as the outside receiver in the Chargers’ Trips Right (three receivers to the right) formation. His arms dangled as he looked at Hall, who initially was rolled up to the line of scrimmage as if he was playing press-man, only to retreat to a cushion and play Cover 3 zone.

As Hall retreated, quarterback Philip Rivers caught the snap and Allen quickly took off. He took a hard right step first and then a left, running full-speed downfield with his knees high and his arms swinging. Near the 40-yard line he finally made a move, slightly opening his right shoulder and sticking his right foot out. Then he bent his knees, sunk his hips, and took three steps before a fourth that rounded his body to the inside. The quick break created a two- to three-yard separation from Hall and if not for an early throw from Rivers, likely a chain-moving catch.

That route was good, but not as good as the one he’d run two quarters later. Down 10 with 3rd-and-3 to go, the Chargers needed a first down. They needed someone (besides Antonio Gates) who they could count on. Allen was their man.

He was lined up once again on the outside of the offense’s Trips Left formation, matched up with Hall, who was shaded outside and set to play press coverage. When it all began, Allen gave a quick left foot outside and then shot back inside, running on the numbers before sinking his hips, chopping his feet, and sharply separating from Hall. He crossed the middle of the field to complete his dig route and acrobatically haul in Rivers’ high throw.

What makes Allen’s routes so good is not his long speed, but his consistency in posture and his short area quickness at the top of his route. He’s able to get in and out of his breaks quickly, leaving cornerbacks well behind. No one was further behind than Amerson later in the fourth quarter when Allen executed a double-move for a 16-yard score.

It was 1st-and-10 with four and a half minutes left in a two score game. The Chargers were down 10 and with the seconds ticking away, they had to score to stay in the game.

To Rivers’ left was a Twins set, two receivers evenly spaced out. One of them was Allen lined up on the far end of the formation as the No. 1 receiver from the sideline-in. He was matched up in tight man-to-man coverage with Amerson, an ultra-aggressive rookie that’s always looking to make a play on the ball. If he wanted to make a big game-changing play, this was his chance.

But Allen had other ideas. He casually released off the line and chopped his feet, performing a “foot-fire” technique prior to kicking out his right leg and opening his right shoulder to the inside, making it seem as if he was going to run a square-in. Amerson jumped inside and then Allen went out. The throw was slightly behind him, but he adjusted, catching it and tapping both feet in to bring the Chargers within a field goal.

Allen’s outstanding play has impressed many this season, including the veteran Gates.

“You don’t really expect it. They talk about his speed and this and that. The boy can play football, and he can get open, ” Gates said. “All that stuff about speed. If you can play and get open, that’s what wins games for you. That’s what makes plays for you. You can get a dog to run and jump. You know what I mean? That’s what this league has underestimated.”

Through seven games he has 527 yards on 34 receptions and 15.5 yards per catch, all because he gets open consistently due to his short area quickness and steady route-running. In the end, that’s what a receiver needs to continually be open and become a star.

That’s what will make Allen a star sooner rather than later.