FN’s 2025 Flames summer prospect rankings – #12: Theo Stockselius

The Calgary Flames got a lot of productive work accomplished at the 2025 NHL Draft.

In the first round, they drafted two very different types of centres: 200-foot WHL ace Cole Reschny and the smaller, speedy Cullen Potter. But with their third pick of the draft, they nabbed a player that, given his versatility, maturity and physical traits, probably shouldn’t have been available where the Flames selected him.

In his first year in the Flames organization, Swedish forward Theo Stockselius debuts in the 12th slot in FlamesNation’s summer prospect rankings.

Theo Stockselius

Centre, Shoots Left
Born July 24, 2007 (age 18) in Norrtalje, Sweden
6’3”, 193 pounds
Drafted in the second round (54th overall) by Calgary in the 2025 NHL Draft

Based on some research, video work and examining Stockselius’ young career from afar, here are a couple conclusions we’ve reached about him:

• He’s a bit of a late-bloomer, in the sense that he didn’t get on the radar of some of Sweden’s larger club teams until his teens.
• Based on his physical attributes and production in the leagues he has been in, the Flames were quite lucky to get him at 54th overall.

A product of Norrtälje, Sweden – a town an hour northeast of Stockholm – Stockselius spent his youth playing in his hometown with Norrtälje IK, then moved onto IFK Täby HC in 2021-22 as a 14-year-old. After two seasons with Täby, he joined Djurgårdens IF as a 16-year-old. (For comparison, 2021 second-rounder William Strömgren, began playing for MoDo Hockey as a 15-year-old, a year earlier than Stockselius… but Stockselius had to deal with the COVID-19 pandemic wiping out pretty much all of his 13-year-old season in 2020-21, which probably contributed to his “slower” progression up the Swedish hockey ladder.)

Regardless, Stockselius has performed quite well offensively over the past four seasons – and that’s without even taking into account that he had a couple surgeries due to a battle with thyroid cancer three years ago. He’s big, he can score, and he can play all three forward positions.

• In 2021-22, as a 14-year-old, he was just over a point-per-game in U16 Division 1 (1.067) and U16 SM (1.125)
• In 2022-23, as a 15-year-old, he was way over a point-per-game in U16 Division 1 (2.609) and U16 SM (2.375), and solid in a small sample in the J18 Region circuit (0.400)
• In 2023-24, as a 16-year-old, he was way over a point-per-game in the J18 Region (1.773) and J18 Nationell (1.600), and solid in a small sample in the J20 Nationell (0.500).
• In 2024-25, as a 17-year-old, he was way over a point-per-game in short stints in the J18 Region (4.000) and J18 Nationell (2.000), and over a point-per-game in the J20 Nationell (1.275).

Most higher-level Swedish prospects spend some time in pro hockey as 16 or 17-year-olds. Stockselius didn’t, which could be because of his slower progression from the regional leagues or just due to Djurgårdens’ stacked system – in addition to Stockselius, in 2024-25 their J20 team featured six other players that ended up being drafted by NHL clubs. That depth combined with Djurgårdens’ pro team pushing for promotion from the second-tier HockeyAllsvenskan to the top-tier SHL probably made pro spots incredibly competitive.

We reached out to a few friends in the scouting community about Stockselius’ season and progression, and a couple of them shared some thoughts.

Lucas Johansson of FC Hockey had these notes:

“Stockselius performed great all year. I really like his ability to make plays under pressure. He can find the tape of a teammate with a pass under a stick or between an opposing player’s legs and that´s an attribute that makes me believe he could be a productive player at a higher level in the future. He played with Viggo Björck in the playoffs and scored 16 points in 9 games helping Djurgårdens win the U20 championship. General Manager of Djurgårdens Niklas Wikegård has said Stockselius is one of the young guys who could get the chance to play in the SHL this upcoming season.”

Dobber Prospects contributor Ethan Lindey provided these thoughts:

“Coming into the 2024-2025 campaign, Theo Stockselius wasn’t on a lot of peoples’ radar but he burst onto the scene and dominated Sweden’s top junior league for Djurgarden. As the season progressed he showed more willingness to drive inside and use his frame to his advantage and grew in his assertiveness with the puck on his stick, trusting himself to make big plays. As if Stockselius’ combination of size and skill wasn’t enough, he displayed exceptional awareness and anticipation allowing him to make plays very few opponents could defend. He’s an extremely raw player with strong tools, and plenty of runway to fill out and develop his agility and speed which could very well be what separates him from others and allows him to impact the game at the next level.”

Expectations for 2025-26

Stockselius was selected by the Western Hockey League’s Seattle Thunderbirds in the CHL’s Import Draft in early July, but he’s headed back to Sweden for the 2025-26 season. After a strong first season with Djurgårdens’ team in the J20 Nationell, he’s likely going to be looked upon as a pace-setter for a club that won their league’s title last year. But he’s also going to be trying to get onto the national junior team’s radar and pushing to make his professional debut in the SHL.

Stockselius was one of the youngest players selected in the 2025 NHL Draft and he’s still got a lot of development ahead of him, physically and mentally. We’re fascinated to see where his game grows between now and when we do next year’s profiles.