Tom Cannon joined Leicester City on a five-year deal
Leicester City boss Enzo Maresca says the club signed striker Tom Cannon knowing he had a stress fracture in his back.
The 20-year-old was a transfer deadline day arrival from Everton.
Cannon had featured for the Toffees in the Premier League against Wolves just six days before making his move to the King Power Stadium.
"Because it is a long-term investment it doesn't mean we don't need him now," Maresca told BBC Radio Leicester.
"But we prefer to be careful with that and make all the checks that we need to do."
The Italian said Cannon's problem was discovered during his medical, but the club pressed on with signing him on a five-year deal for an undisclosed fee.
Maresca says he still cannot put a timeframe on the Republic of Ireland Under-21 international's recovery.
"We found a problem when he signed. At the moment he is not even training with us, so it will be quite long-term I guess," Maresca said.
"We still don't know how long. He didn't train any sessions with us."
Cannon, who made just four first-team appearances for Everton, spent last season in the Championship with Preston, where he scored eight goals in 20 league appearances.