Note: This is SB Nation NHL’s top 25 players under age 25 series! We’ll be covering each player from No. 25 to No. 1 over the next few weeks leading up to training camp time. See the complete list and information on how the rankings were compiled.

When the Toronto Maple Leafs exploded on the scene last season as the NHL’s funnest young team to watch, the attention was squarely on the seven rookies who played over 50 regular season games. Among that crop was Mitch Marner, a 20-year-old switch center and right wing who made up Toronto’s three-headed dragon with Auston Matthews and William Nylander.

It shouldn’t be much of a surprise that Marner broke out in his rookie year. After all, he was a fourth overall pick by the Maple Leafs in the 2015 draft, and just one of many top-10 picks Toronto hoarded over the past few seasons. Not all top picks pan out, of course, but the Maple Leafs have seemingly struck gold after the riches their previous season brought them.

Marner put up 61 points in 77 games with 19 goals to his name in the 2016-17 season. His 61 points on the year put him in a three-way tie for third place on the Maple Leafs team leaderboard and his 42 assists were tops on the team, which set a Toronto rookie record. It was an astonishingly good year for Marner in his first NHL season, and his addition on the second line with James van Riemsdyk and Tyler Bozak were just as deadly as Toronto’s first line.

In fact, the line of van Riemsdyk, Marner, and Bozak led the NHL with 48 even strength goals this past season, according to Left Wing Lock.

Marner spent almost all of his time on the second line as the latter half of the Maple Leaf’s one-two punch, benefiting both van Riemsdyk and Bozak at even strength GF% due to Marner’s extreme playmaking abilities. However, van Riemsdyk was a slightly better Corsi player away from Marner in their limited time apart, jumping from a 50.74 CF% player with to a 56.32 CF% player without the rookie, per Natural Stat Trick. Marner himself was a just above-average Corsi player, with a 50.17 CF% percentage at five-on-five this season, though clearly his play-driving benefits outweigh his average possession stats.

While the Maple Leafs have a plethora of young stars that all deserve time in the spotlight, Marner is no doubt in a higher tier. His rookie season was testament to his skills as a dynamic playmaker, and he’ll no doubt continue rising as his career progresses.

Past accomplishments

Marner spent three seasons in the OHL with the London Knights, amassing a total of 301 points in 184 games, with 205 of those being assists. In two of his three seasons in London, Marner put up north of 100 points in seasons of 63 and 57 games. While Marner fell just short of the OHL rookie of the year award in 2014 after registering 59 points in 64 games, he lead the Knights to an OHL Championship win — and a Memorial Cup — in 2016 as co-captain of the team.

That season, Marner also won the Red Tilson Trophy as the league’s most outstanding player of the year and led the Knights with 44 playoff points in 18 games en route to a successful final year at the major junior level.

In the NHL, Marner finished fifth in Calder Trophy voting after his tremendous rookie season. Marner also won rookie of the month honors in January after posting 15 points in 13 games for the Maple Leafs. After a strong season that ended in the first round at the hands of the Washington Capitals, Marner went on to help Team Canada to a World Championship silver medal with 12 points in 10 games.

All in all, quite the decorated past for Marner.

Future impact

The Maple Leafs are truly blessed to have a top-line talent in Marner occupying space on their second line. Though Marner didn’t fill a center role for the Maple Leafs last year, he’s familiar with the position enough that it’s what NHL.com lists him under when you pull up his stats.

Regardless, Marner’s position on the second line gives Toronto the one-two punch championship teams have, from Sidney Crosby and Evgeni Malkin with the Penguins to Jonathan Toews and Patrick Kane with the Blackhawks. With Marner on his entry-level deal for the next two seasons, the window remains wide open for the Maple Leafs to do serious damage with one of the NHL’s most skilled forward corps.

With no trade winds currently blowing, Marner will likely be back with van Riemsdyk and Bozak for the upcoming season, and their chemistry could very likely propel them to the top of the NHL’s leaderboards once more. Marner saw an average of 16:49 minutes per night, and given his offensive talents it’s not unreasonable to think the second line will receive a bump in minutes.

For good reason, as Marner no doubt projects to be a member of the Maple Leafs core for the near — and likely far — future. Marner arrived in the NHL last year to incredible fanfare, and it’s very likely the young forward will keep the pace in the upcoming years to come.

Is this ranking too high or too low?

Maple Leafs fans will likely exclaim that this ranking is too low for Marner and in time that could very well be the case. Given the 20-year-old has played just one season — though an incredible one it was — there’s a reason he’s ranked at No. 17 on the list.

Should Marner progress the way he’s trending as an offensive forward, he’ll no doubt jump up this list. It’s likely only a matter of time.

Highest rank: No. 3

Lowest rank: Not ranked