Merkley recorded his second career three-point game four days later, as he scored two goals, including the overtime winner, while adding an assist in a 4–3 win over the Kingston Frontenacs.
Just over a month later, on December 15, Merkley scored a goal and three assists for his second career four point game in a 5–4 victory over the Kingston Frontenacs.
Merkley finished the regular season with 13 goals and 67 points in 63 games for the Storm, helping the club reach the post-season.
On March 23, Merkley appeared in his first career OHL post-season game, earning an assist in a 7–2 loss to the Kitchener Rangers.
On March 9, Merkley recorded his first two-goal game with the Petes, scoring twice, as well as adding an assist, in a 5–4 win over the Barrie Colts.
At the start of the 2019–20 season, it was announced that Merkley was traded from Peterborough to the London Knights in exchange for future draft picks.
[5] Following the conclusion of his junior season in 2018–19, the Sharks assigned Merkley to their American Hockey League affiliate, the San Jose Barracuda.
Approaching the 2022–23 season, Merkley was unable to make the Sharks opening roster, and was assigned to continue his development in the AHL with the Barracuda.
Merkley added 14 assists through 30 games with the San Jose Barracuda before remaining a healthy scratch after requesting a trade away from the Sharks organization on January 1, 2023.
[8] Merkley's trade request was accommodated when he was dealt, along with Matt Nieto, to the Colorado Avalanche in exchange for fellow 2018 first-round pick Martin Kaut and defenceman Jacob MacDonald on January 25, 2023.
Merkley made 28 regular season appearances with the Eagles, contributing with 2 goals and 8 points, however, was a healthy scratch for the club through the playoffs.