The 35-year-old Nigeria striker is yet to play a competitive game since he left the Chinese Super League club in 2018 after tearing his hamstring.
With Ighalo closing in on a permanent deal at Manchester United after his impressive start to his loan, Martins has emerged as an option for the Shanghai outfit and he has returned to the Asian country to finalise paper work.
The former Inter Milan and Newcastle United attacker scored 20 goals across all competitions during his first stint in China, and also won the Chinese FA Cup in 2017.
Martin’s imminent return to Shanghai Shenhua could play a vital role in United’s permanent move for Ighalo at the end of his loan spell on May 31.
The 2020 Chinese Super League is yet to start due to the outbreak of the coronavirus pandemic, it was initially scheduled to commence on February 22 but it has been postponed to April 18.