Portsmouth chief executive Peter Storrie has admitted the club considered a deadline day move for Benjani but fears over his fitness ended their interest.
The 31-year-old joined Pompey from Auxerre in January 2006 for £4.1million before departing to join Manchester City in February 2008.
The Zimbabwe international has scored just six goals in 24 appearances in all competitions in his time at Eastlands largely due to a string of injuries.
The striker finds himself well down the pecking order at City following manager Mark Hughes' extravagant summer spending and was believed to be on his way out of the club.
Benjani was subject of interest from Hull City last week but the move broke down after the player failed to agree personal terms with the Tigers.
Many expected the frontman to return to the South Coast before the window shut on Tuesday, after building a strong rapport with the Pompey faithful during his two years at the club, however a deal failed to materialise.
"It was something we looked at but he has injury problems," Storrie explained to The News.