[7] He scored his first goal for Genk in their 2–0 UEFA Europa League play-off round win against Swiss opponents FC Luzern, in the 88th minute, on 30 August 2012 at the Cristal Arena.
The following season, he was loaned back to the second tier to play for Heilongjiang Lava Spring, though he also scored seven goals in 14 games in the top flight for Beijing Renhe.
On 31 January 2020 – transfer deadline day in England – Masika joined EFL Championship side Reading on loan until the end of the season.
[20] Masika was meant to play in a 2013 Africa Cup of Nations preliminary round match against Togo on 29 February 2012, but could not fly back to Kenya as he had club commitments with Genk that day.
[21][22] However, he made his international debut for Kenya against South Africa on 16 October 2012, coming on as a substitute for Thika United forward Francis Kahata in the 61st minute.