"I made a decision and I followed my heart. Santos is not just my team, it's my home, my roots, my history, and my life," the 33-year-old forward said in a statement from the club.

Neymar started his career at Santos before moving to Barcelona and then Paris Saint-Germain. After an injury-hit spell in Saudi Arabia, he returned to Santos in January on a contract that was due to expire on June 30.

The injury problems that restricted him to just seven matches in 17 months at Al-Hilal persisted.

He has played 12 matches in five months across all competitions for Santos, scoring three goals. In his last appearance in the domestic league, he was sent off for  a second yellow card after scoring with his hand against Botafogo.

After 12 matches in this season's Brazilian championship, Santos are only clear of the relegation places on goal difference.

Since his return to Brazil, Neymar has drawn criticism for partying at the Rio Carnival and for appearing in the gimmicky seven-a-side Kings League while nursing injuries.

Neymar is the Brazil national team's all-time leading scorer with 79 goals, two more than another Santos product, Pele, but his quest for a World Cup winner's medal has repeatedly ended in disappointment.

Neymar was recalled to the Brazil squad in March for two World Cup qualifiers, but withdrew  with a thigh injury.

In May, new coach Carlo Ancelotti left Neymar out of his first squad.

"I selected players who are in good shape. Neymar has just returned from injury, everyone knows he's a very important player and we're obviously counting on him," said Ancelotti.