"It's something you kind of have to go through in order to understand," Werenski said. "I shouldn't say 'hit the wall,' but you kind of start to feel it. You can really feel it."

This is what they mean by the 'rookie wall.'

COLUMBUS -- At 19, Zach Werenski felt like an old man. He would wake up tired. His body would be sore all over. He'd shuffle on the walk from his place to Nationwide Arena, where he plays for the Columbus Blue Jackets, stretching his back and legs on the way. He'd stretch some more to get ready for games but would just want to go sit down, exhausted when he should have been energized.

Now that Werenski has gone through it -- no, now that he has broken through it -- you can appreciate his season all the more. With 46 points (11 goals, 35 assists) in 71 games, he is tied for fifth among rookies and eighth among defensemen. He runs the NHL's seventh-ranked power play. He's a key reason the Blue Jackets have set records for wins (47) and points (100), have made the Stanley Cup Playoffs for the third time in their 16-season history, and are in a tight race for the Presidents' Trophy. He should be a candidate for the Calder Trophy.

"I've got a special guy here," coach John Tortorella said, "because he's understanding really quickly what it is to be a pro."

Werenski, the No. 8 pick of the 2015 NHL Draft, spent the past two seasons at the University of Michigan. A typical week for the Wolverines would go like this: easy practice Monday, hard practices Tuesday and Wednesday, easy practice Thursday, games on Friday and Saturday. He played 35 games in 2014-15 and 36 last season.

The first quarter of this season, Werenski was running on adrenaline. He was playing in the NHL, a dream come true. Everything was new and exciting. He had 16 points (five goals, 11 assists) in his first 19 games. His body felt good.

Video: CBJ@PHI: Werenski buries one-timer through traffic

But then the adrenaline wore off, and the grind wore on -- back-to-back games, three games in four nights, late-night flights. Opponents recognized his talent and started hitting him more often. His body felt tired and sore like it never had before.

"The thing you hear a lot is, 'You're young. You have a lot of energy,' " Werenski said. "You do. But the schedule just takes it out of you."

The physical challenge became a mental challenge. Tortorella told him, "If you think you're tired, you're going to be tired." So he'd tell himself, "I'm not tired. I'm not tired." He'd ask assistant coach Kenny McCudden to go on the ice for 20-30 minutes before practices to do drills so he could feel the puck better. He'd go through longer off-ice warmups, riding a stationary bike before games for the first time in his life. He'd go through harder on-ice warmups, trying to sweat more to get his body going.

"He understood how to play with soreness and not leaving because you're sore," Tortorella said. "I think you only leave the lineup when you're hurt. I think he understands that at a very young age."

Blocking out fatigue and soreness was easier said than done, especially when he dealt with a virus from late January to early February. Werenski came back from the four-day All-Star break Jan. 31 thinking he would feel better but got even sicker. He couldn't wait for the Blue Jackets' five-day break from Feb. 20-24.

"I had it circled on my calendar," Werenski said. " 'Five days off. Five days off.' "

Werenski had a goal and two assists against the Nashville Predators on Feb. 19, boosting his confidence, then went to Miami with friends for three days. He lay in the sun doing nothing. He came home to Grosse Pointe, Michigan to see his family and slept in his old bedroom with his old jerseys on the walls, a stark reminder that he was still just a teenager.

Video: NSH@CBJ: Werenski picks the corner with great shot

"You and I at 19, were we out of our house at that time?" Tortorella said. "I don't know. But we're expecting these guys to play at the top level of their profession. So that was a good time for him, and I think it gave him some juice."

When Werenski returned, he was rejuvenated. From Nov. 26 to Feb. 19, he had 20 points (four goals, 16 assists) in 39 games. He had one point in seven games in a stretch, one in nine in another. Since Feb. 26, he has 10 points (two goals, eight assists) in 12 games.

Tortorella raves about how Werenski sees the game, doesn't panic and isn't afraid to try the same play after making a mistake. He pays him what he considers the biggest compliments he can pay a player: that he carries himself like a pro and respects the League.

"He gets it," Tortorella said.

The Blue Jackets play the Toronto Maple Leafs on Wednesday (7 p.m. ET; SN, TVA Sports, FS-O, NHL.TV) in a potential preview of the Eastern Conference First Round, the Washington Capitals on Thursday in a key battle in the Presidents' Trophy race, and nine regular-season games after that.

But Werenski can see the finish line and feels ready for what lies beyond. About this time last year, he left Michigan and joined Lake Erie (now Cleveland) of the American Hockey League, playing seven regular-season games and 17 playoff games, helping the Monsters win the Calder Cup. He's looking forward to April, May and June, but not to rest.

"Obviously," Werenski said, "the fun stuff starts when the regular season ends."