Dallas is suffering with an ankle problem while Lasogga has not recovered from a leg injury picked up in training last week but midfielder Eunan O’Kane (hip) could feature.
O’Kane’s midfield partner Ronaldo Vieira will be available after serving a one-match suspension following his sending off in the 4-1 defeat at Wolves.
Dallas damaged his ankle in the first leg of Northern Ireland’s World Cup qualifier against Switzerland but played the full 90 minutes in the second leg three days later.
When asked if he could have been available, Leeds head coach Thomas Christiansen said: “There could have been a possibility against Villa, but I didn’t want to run any risk.
“He already took that playing the two games with his national team which were a bad decision for the future. But there is nothing that we can say and do right now, just get him as fit as soon as possible.”
Lasogga, on a season-long loan from Hamburg, was also close to making the squad.
“He could have had the possibility,” Christiansen said. “He had joined the training individually, but next week he will probably join the team.”
Leeds have won two of their last three games but sit outside the…