Sri Lanka Cricket chief executive Duleep Mendis said the move would help the team, which has slipped from second to sixth position in One-day rankings after losing eight of their nine one-dayers in the past two months.
"We are in serious trouble," Mendis told reporters here on Wednesday.
"I can see the body language (of the players) and it is clear the team has lost confidence. Mentally, they are down. It is a very important time. Hopefully, we will benefit out of it."
Sri Lanka, thrashed by India in both Test and one-day series recently, have also lost two consecutive one-dayers on the current tour of New Zealand.
They leave for Australia next week for a tri-series also featuring South Africa.
South African Gordon will have two sessions with the Sri Lankan team, the first at Melbourne on January 9 and then at Perth in the first week of February.
Gordon also worked with the Sri Lankan cricketers before their Test series victory over the West Indies at home last year.
"In a situation like this, this is what is needed more than fitness and play on the field. We have to give the players back the confidence because we are approaching the World Cup (in 2007)," said Mendis, a former Sri Lankan captain.
He said coach Tom Moody and captain Marvan Atapattu would also be asked to explain the team's recent dismal performance.
"Moody and Marvan will have to do a lot of explaining," he said.
Former Australian one-day specialist Moody took over as Sri Lanka's coach in May with the aim of preparing the team for the 2007 World Cup in the West Indies.