Coventry City could be without Yakubu for the rest of the season if his hamstring tear is confirmed as serious.
The Nigerian, who is on a short term contract, came on as a substitute for the Sky Blues in their 3-1 defeat to Swindon Town at the Ricoh Arena and came straight on for Marcus Tudgay in the 70th minute without warming up.
Yakubu soon tore his hamstring and had to walk round the pitch as he was unable to run.
The striker, who set up George Thomas' consolation goal, was seen trying to come off with a couple of minutes to go but City boss Russell Slade refused to let him come off the pitch.