The Brazilian playmaker has impressed since seemingly shrugging off his early-season injury problems, scoring five goals in his last 11 appearances.
But what proved to be a dark day for Wanderers at the Madejski Stadium kicked off on a bad note when Moritz pulled out of the squad on Friday with a sore knee.
The 27-year-old was issued with a protective knee brace and was checked over by the club’s medical staff yesterday.
The hope at present is that he will be available for this weekend’s FA Cup fourth round tie against Cardiff City.
Moritz struggled to stay fit at the start of his Wanderers career, making his first start against Huddersfield Town in early November.
A groin injury kept him out for two months – and he has since made just six starts for the Whites, the last of which was in the third round FA Cup victory over Blackpool.