As a 20-year-old in his AHL rookie campaign, Ostlund tallied 19 goals and 36 points in 45 games. His season was interrupted in late October by a hand injury which required surgery. He returned on December 20. After scoring just one assist in his first 12 games, his pace surged in January as he scored 35 points in his remaining 33 appearances. He was named the AHL’s rookie of the month for March and the league’s player of the week for the week ending March 30, 2025. His proficiency at both ends prompted the Buffalo Sabres to recall him to the NHL on April 4. He played eight games with Buffalo whilst receiving an average TOI of 10:33. He failed to make an impact on the score sheet and recorded a plus-minus of minus-six. During Rochester’s 2025 Calder Cup playoff run, Ostlund scored two assists in eight games.

Ostlund has had a strong start to his first full SHL campaign with Vaxjo HC. He currently has eight goals and 17 points in 24 games with his club, scoring at a similar near-point-per-game pace to the team’s scoring leaders at the age of nineteen. His strong showing at the 2024 World Juniors helped earn Team Sweden a silver medal. He scored a crucial goal and assisted on another insurance marker in the semifinal game against Team Czechia. Ostlund applied pressure and created plays with his slick skill set throughout the tournament, in which he scored three goals and ten points in seven games — tied for Team Sweden’s scoring lead alongside regular international tournament linemate Jonathan Lekkerimaki.

Ostlund finished his 2022-2023 Allsvenskan regular season with eight goals and 26 points in 37 games, a successful year for the 18-year-old if not for his subsequent playoff campaign which was ultimately derailed by injuries. He was fourth among regular-season scorers for his team, Djurgardens, but during the playoffs was relegated to the fourth line while he struggled to return to form. Ostlund is a quick, agile playmaker whose game revolves around his distribution and transition abilities. He can shield and protect the puck individually to create offense, but he currently lacks heaviness and strength in his game. His contributions to his team’s forecheck and his possession work down low need to improve. The 2023 Allsvenskan playoffs have concluded; thus, Ostlund is slated to join the Rochester Americans for the remainder of the AHL postseason as a member of their practice roster, although he is not expected to participate in their upcoming matches this spring.

Östlund has been selected by the Buffalo Sabres in the first round of the 2022 NHL Draft, 16th overall.

Östlund has been a highly touted prospect in this class for some time but a disappointing performance at last summer’s Hlinka Gretzky Cup raised questions about his place among the top names in the 2022 draft. He has had a solid start to his season though, and his raw tools are still very intriguing.