Gallacher, who had scored Blackburn's second goal on his comeback following a 15-month absence with a double fracture of the same leg, was injured by a challenge by Palace's John Humphrey. He returned from hospital up to his waist in plaster and confirmed yesterday that X-rays revealed a crack on the bone.
"It's a nightmare, though I surely can't be out for as long as last time," Gallacher said. "It will be at least 12 weeks before I can think about kicking a ball. All I've got to look forward to is pre-season training.
"This is a massive blow. To not play for so long and then to score was unbelievable. I was on such a high. Now I'm in a major low."
Gallacher, a £1.5m signing from Coventry, had been pencilled for Scotland's Asian mini-tour this summer and was being watched against Palace by David Hay, Celtic's assistant manager.
n Arrigo Sacchi, Italy's coach, surprised no one yesterday when he recalled Roberto Baggio into his squad for Italy's European Championship qualifier against Lithuania next week. Sacchi, who had to leave a recuperating Baggio out of his side for last month's qualifiers against Estonia and Ukraine, named a 19-man squad for the 26 April Group Four match in Vilnius.