Meriläinen previously played with the Oulun Kärpät of the top-tier Finnish Liiga and at the major junior level with the Kingston Frontenacs of the Ontario Hockey League (OHL).

Meriläinen joined Oulun Kärpät of Finland's top-tier Liiga as a young player, rising quickly within the team's development ranks.

[3] The Senators asked Meriläinen if he would join the Kingston Frontenacs of the Ontario Hockey League (OHL) for one season.

[1] During the 2022–23 Liiga season, Meriläinen rejoined Oulun Kärpät and established himself as the starter, having a terrific year with the team.

[5] Following the conclusion of Oulun Kärpät's season, Meriläinen returned to North America to join Ottawa's American Hockey League (AHL) affiliate, the Belleville Senators.

However, neither he nor his replacement in net, Søgaard, played well and Ottawa lost the game 7–2 to the Panthers and were officially eliminated from the playoffs.

[13] He made one appearance in the 2024 Calder Cup playoffs, a loss to the Toronto Marlies, stopping 27 of 29 shots he faced and letting in only two goals.