Rio De Janeiro, April 19 -- Santos forward Neymar has been diagnosed with a new leg muscle injury, the club confirmed, marking the latest setback in his protracted struggle to regain full fitness.

The 33-year-old was forced off in the 34th minute of Santos' 2-0 victory over Atletico Mineiro on Wednesday and subsequent tests identified damage to the semimembranosus, one of the hamstring muscles.

In a statement on its official website on Friday, Santos said the latest injury was not a reoccurrence of a previous problem.

"The number 10 has already started treatment and ... will continue muscle strengthening work," Santos said, without providing an estimated timeframe for his recovery.

Neymar has struggled with a series of soft-tissue ...