Hull midfielder Robert Snodgrass has been ruled out for six months with a dislocated kneecap suffered during his Tigers debut at QPR on Saturday.
Manager Steve Bruce revealed the extent of the injury to Snodgrass, who must also undergo scans to investigate possible ligament damage, ahead of the Europa League qualifier against Lokeren in Belgium on Thursday, the club's official website said.
The Scotland international was one of Bruce's big summer signings, arriving from Norwich in a seven million pound deal.
The 26-year-old pulled up with a suspected twisted knee in the first half of his side's 1-0 win at Loftus Road.
He wrote on Twitter: "Gutted ....!!! But I will work as hard as I can to come back fitter and stronger."
Gutted ....!!! But I will work as hard as I can to come back fitter and stronger ��- Robert snodgrass (@robsnodgrass7) August 20, 2014
Bruce now faces a race against time to boost his squad.
His central defender son Alex is ruled out with a back injury and, following the sale of Shane Long to Southampton last week, the manager said he needed to act before the transfer window closes.
Bruce told reporters prior to the flight to Belgium: "We're trying to add to the squad, as we know we have to -- we've lost two big players in the last week.
"We didn't envisage losing Snodgrass for six months, which is a big blow for us because he was brought in to give us that little bit of quality in the midfield area.
"We've got 10 or 12 days to try to bring in a replacement, and two or three offers went out in the last 24 to 48 hours."
Bruce said he would field a much-changed lineup against Lokeren, who are currently seventh in the Belgian Jupiler League with two wins from their first four games.
Yannick Sagbo is expected to return from suspension to partner Sone Aluko up front, while Maynor Figueroa is also expected to figure after starting on the bench at QPR.
Bruce added: "I will be changing my team around and giving the players who got us into Europe last year the chance to play in Europe."