TORONTO — As the Toronto Maple Leafs rebuild around young players, they sometimes take one step forward and two steps back.

Teenagers like Edmonton’s Connor McDavid and Winnipeg’s Patrik Laine are among the N.H.L.’s top scorers, but the learning curve is steep for rookie forwards, even those with obvious skill.

The Maple Leafs have one of the league’s youngest rosters, led by the 19-year-olds Auston Matthews, the No. 1 overall draft pick this year, and Mitch Marner, the No. 4 pick in 2015.

Connor Brown, 22, and William Nylander, 20, saw some time with the Maple Leafs last season, but they, too, are learning to navigate the rocky shoals of the N.H.L.