Tracy McGrady has admitted that he thought about using performance-enhancing drugs during a battle with a knee injury in 2008.

The 34-year-old, who retired from the NBA in the summer, revealed that he had lost confidence in his ability to compete with the best players and that illegal substances had come under consideration.

"Just because the era that we [were] in, especially baseball with a lot of guys doing it, obviously they're doing it to stay healthy, to stay on the field or to stay at that level they were playing; I considered doing that," McGrady told NBA TV's Open Court.

"Because I was playing at such a high level for so many years, and when I had my knee injury, I was doing everything in my will power to get back to that level.

"I actually considered — I considered — getting an advantage. And whatever that was, doing it illegally ... I considered that to get back."

McGrady was voted onto the NBA All-Star team on seven occasions during his career.