The career of star sprinter Hay List is in the balance with the triple Group One winner battling a knee injury.Hay List suffered the injury after undergoing emergency surgery last Friday for colic.Scans on the injured knee will be sent overseas for analysis with trainer John McNair and the Davenport family which owns Hay List saying it was not necessarily the end of the six-year-old's career.The hulking sprinter has a history of leg problems and injuries over the past few years but has overcome

The career of star sprinter Hay List is in the balance with the triple Group One winner battling a knee injury.

Hay List suffered the injury after undergoing emergency surgery last Friday for colic.

Scans on the injured knee will be sent overseas for analysis with trainer John McNair and the Davenport family which owns Hay List saying it was not necessarily the end of the six-year-old's career.

The hulking sprinter has a history of leg problems and injuries over the past few years but has overcome those to rise through the sprinting ranks in the eastern states after doing his early racing in Perth.

As well as winning three Group One races, Hay List has racked up four seconds at the top level behind Black Caviar.

He got his moment in the sun this autumn when he carried a hefty 58.5kg to win the Newmarket Handicap (1200m) at Flemington last month.

He had some problems with a foot abscess leading up to his most recent start when he was beaten by three-year-old Foxwedge in the William Reid Stakes.

Hay List has won 15 of his 23 starts and run second on six occasions, earning more than $2.5 million.