Leeds United will have to start the new Championship season without striker Luciano Becchio.
The Argentine forward, who scored 20 goals last season, has undergone surgery on his hamstring injury.
Manager Simon Grayson told the club website: "Luciano has had the operation and will miss the start of the season."
No time scale has been given on Becchio's return but Leeds are already without fellow striker Davide Somma for six to nine months.
Better news for Grayson is the return to fitness of defender Patrick Kisnorbo and midfielder Lloyd Sam, both of whom are in contention for Saturday's friendly at Sheffield Wednesday.
The pair, along with striker Robert Snodgrass, missed the midweek win at Rochdale.
"Paddy Kisnorbo and Lloyd Sam both trained on Thursday," Grayson said.
"Snodgrass is touch and go, and there's one or two with knocks who might not make it.
"Billy Paynter has tonsillitis as well so he won't be playing."