Sprinting legend Michael Johnson believes Wayde van Niekerk can come back as strong as ever from his knee surgery.
The South African superstar, who broke Johnson's 400m world record at the Olympics last year, tore his anterior cruciate ligament and meniscus cartilage during a celebrity tag rugby game three weeks ago.
Van Niekerk underwent surgery at the Steadman Clinic in Vail, Colorado on Tuesday night and will now follow a rehabilitation process that will keep him sidelined for between 6-9 months.
Johnson admits it is an unusual injury for a sprinter, but points to the example of NFL players in saying that Van Niekerk can bounce back and continue to dominate athletics.
He tweeted: "Better '18 season than '19 or '20. Can't think of a past sprinter with a torn ACL. Plenty of NFL players come back just as strong."
Van Niekerk will miss the 2018 Commonwealth Games in Australia, where he was to also set compete in the 100m and 200m.