The Oilers went 10-5-0 in their next 15 games. When they left for Christmas break, they were still in the playoff race. But after they returned, they went 1-6-1 in their next eight.
"All of a sudden, you're out of it again," McDavid said. "And then we had a couple injuries and whatnot. It's tough to battle back. Obviously there is a bit of a snowball effect. Especially as you get later and later and your time starts going against you, it can get frustrating."
The Oilers shook up coach Todd McLellan's staff, replacing assistants Jim Johnson, Jay Woodcroft and Ian Herbers with Glen Gulutzan, Trent Yawney and Manny Viveiros.
But they made few roster changes in the offseason, signing center Kyle Brodziak, forward Tobias Rieder, goaltender Mikko Koskinen and defenseman Kevin Gravel.
Defenseman Andrej Sekera, who missed 46 games last season because of a torn knee ligament, is out indefinitely because of a torn Achilles tendon.
Unless general manager Peter Chiarelli makes a major move, the Oilers must get more out of the same players. Forward Milan Lucic went from 23 goals in 2016-17 to 10 last season; he must be better. Goaltender Cam Talbot went from a .919 save percentage to a .908; he must be better. And so on.
McDavid made headlines by saying he wants to score more. But he can't do it alone, and goals aren't the goal, anyway.
"Obviously I get paid to score and create chances, and that's what I have to do," McDavid said. "But just at the same time, I have to be able to be responsible defensively, good on face-offs, all the little things that coaches love and that win games. I think that's the main thing. You want to win hockey games, and it doesn't really matter how you do it."