It has always been hoped that Hussey, Durham's captain in 2005, would return to the club when his Test days were over. But they are unlikely to be able to compete with the lure of the Indian Premier League and the need to spend more time with his four children.
Collingwood said: "I can't believe Mike has retired from international cricket. He was a seriously tough competitor with an amazing record."
Onions added: "It was a privilege to play with Huss back in 2005, when he changed Durham as a club. He was professional, determined and a nightmare to play against."
Durham's run of four successive championship wins, which hauled them out of relegation trouble last season, equalled the club record set in the first four matches under Hussey's captaincy.
They would dearly love to make a similar start next season, especially after failing to win any of their first ten this year.
At that point finding a top overseas batsman for 2013 was their priority and Hussey's name was mentioned as there was a suspicion his international days might be nearing an end.
He opted out of Australia's one-day matches in England last summer because of the premature birth of his fourth child, but it quickly became obvious afterwards that he was still seen as an essential member of the side.
His announcement that he will retire after the current series against Sri Lanka has therefore come as a surprise, even at 37.
He plans to continue playing for Western Australia as well as banking the riches on offer in the Indian Premier League - something with which Durham could not hope to compete.
They have recently scaled back their search for an overseas batsman, partly for financial reasons, but might still have fancied signing Hussey for the first two months of the season.
They have eight championship games to play by mid-June but if, as expected, Hussey is again involved with Chennai Superkings his IPL commitments will keep him busy until late May. He is unlikely to want to come to England after that ahead of an Ashes series from which he has opted out.
Hussey revealed that his decision had been confirmed by a waning desire for the looming tours of India and England.
Known universally as "Mr Cricket", this most diligent of batsmen could not find his usual enthusiasm for the 2013 schedule.
"I've known for a while that I probably wanted to finish at the end of the Australian summer," he said. "I just wanted to see how I felt throughout the summer and my feelings hadn't really changed. I didn't have the same excitement or buzz about the challenges ahead.
"I still feel like I'm playing well. But it's more to do with everything else around the game, time away from home, the constant travel, the constant training, the constant pressures and stresses involved with international cricket. They eventually take their toll on you."
Although Hussey missed part of Durham's 2005 season because of one-day international duty, it seemed that a Test career might have passed him by. But at the age of 30 he was belatedly awarded a Test cap in November 2005, having scored 15,313 runs at first-class level to earn it.
He was contracted to return for a second season with Durham, but his instant success at Test level meant he became a fixture in the Australian side and he has not missed a Test match in seven years.