The 24-year-old had made eight appearances for Paolo Di Canio's in-form side since joining on loan in November.
And despite having failed to get on the scoresheet, Di Canio believes there is more to come from the forward and wants to keep hold of the former Crystal Palace man for longer.
"I am very happy to have Chris here for more time," he told the club's official website.
"The new agreement means he is here for another five games but we will be working within that month to try and keep him here for longer.
"He has done well for us so far. We know he can score goals because he scored seven goals in the Championship last season.
"He has played a big part since he came here and we are pleased to have him here for longer."
Meanwhile, the Italian remains hopeful of securing an extended deal for Charlton midfielder Danny Hollands.
- Sports & Recreation
- Paolo Di Canio