Neymar is expected to undergo treatment and rehabilitation lasting four to six weeks after suffering a hamstring injury, Al Hilal confirmed on Wednesday, intensifying speculation over the Brazilian's future with Saudi Arabian club.

Neymar made his second club appearance following a 12-month injury layoff by coming on as a substitute in the 58th minute of Al Hilal's 3-0 win over Esteghlal of Iran in the AFC Champions League Elite on Monday.

The former Barcelona star then pulled up after stretching for the ball with three minutes remaining and had to be replaced.

"Unfortunately, it is not a simple injury and he seems to be suffering from muscle pain and it is not a knee issue," Al Hilal coach Jorge Jesus said Wednesday in a news conference in Riyadh.

Neymar took to social media to update his fans.

"Hopefully nothing too much" he wrote. "It's normal that after one year [out] this happens, the doctors had already warned me, so I have to be careful and play more minutes."

Saudi Arabian media speculated that Al Hilal may not register Neymar, whose contract ends in June 2025, for the second-half of the Saudi Pro League season.

Neymar has played just seven games for the 19-time Saudi champion since signing in August 2023 for a reported fee of $90 million. He is not currently registered to play domestic league games as the club has a full contingent of 10 foreign players, but is allowed to play in continental competitions.

A new registration window opens in January.

Information from the Associated Press contributed to this report.