The 24-year-old enjoyed a season long stay with the Hammers from Inter Milan last season but he prevent the club from slipping out of the Premier League.
Obinna initially turned in a number of eye catching performances at Upton Park before tailing off towards the end of the campaign, but he showed enough potential to impress City boss Tony Pulis.
The player has previously made noises about preferring a move to another Italian side if things didn’t work out for him at Inter, which could scupper the hopes of both Pulis and Fulham boss Martin Jol, who are scouring the transfer market for some potential bargain buys to strengthen their squads.
Rangers centre-back Russell Martin will miss Scotland's friendlies against Costa Rica and Hungary through injury.
Jonathan Walters is ready to continue his Republic of Ireland career when he returns to full fitness, according to Martin O'Neill.