Parramatta have been rocked ahead of their semi-final against South Sydney with Michael Jennings stood down for testing positive to performance-enhancing substances.

Just hours out from kick off, Jennings was on Saturday morning provisionally suspended by the NRL after they were informed he returned a positive test last month.

The NRL said the 32-year-old had tested positive to Ligandrol and Ibutamoren, both of which are banned by the World Anti-Doping Agency.

It leaves the veteran Eel and former NSW and Kangaroos centre’s career in jeopardy as he tries to clear his name.

“Michael Jennings has been stood down from today’s game and ongoing training and playing responsibilities while the process runs its course, which under the policy includes the opportunity to have his B-sample analysed,” the Eels said in a statement.

The news comes at the worst possible time for the Eels, who are already without wingers Blake Ferguson and Maika Sivo for Saturday night’s semi-final.

-AAP