The 29-year-old suffered a muscle strain on the back of his left thigh in Porto's goalless draw against Vitoria Guimaraes on Monday night and was stretchered off immediately in the 76th minute.
Marega who is the leading top scorer in Sergio Conceicao's team with 16 goals across all competitions this season is expected to be miss two months of competitive football as he continues recovery.
In the past few months, the talisman has cemented his place as Porto's target man upfront since Cameroon's Vincent Aboubakar ruptured the anterior cruciate ligament of his left knee back in September.
Marega, scorer of five goals in six Champions League games this campaign, will also miss both legs of Porto's round of 16 tie against Roma.
The Estadio do Dragao outfit are in the running to clinch their 29th Primeira Liga title this season as they currently lead the standings with 50 points from 20 matches.