Merkies began his professional career in 2022 by taking a gap year off university, having been promoted to the HKFC first team ahead of the 2022–23 Hong Kong Premier League season.

[1][2] The young winger made his league debut in a 1–0 victory over Sham Shui Po in the opening day fixture.

[7][8][9] He went on to take time off school and announced his decision to pursue football as a full-time passion prior to signing with Southern.

[10] Merkies netted his first goal for Southern in once again a Hong Kong Sapling Cup tie against his former club HKFC in a 2–2 draw away from home.

[14] After acquiring his HKSAR passport, Merkies was named in the 52-man preliminary squad in preparation for the national team's friendly fixtures for November 2024.