Milos Raonic, the 2016 Wimbledon runner-up, has withdrawn from the French Open a week before the clay-court Grand Slam tournament begins.

Raonic says on Twitter on Sunday that he needs "to continue working hard to put myself in the best position when I step out on the court."

He hasn't played since a straight-set loss to fellow Canadian Denis Shapovalov at Madrid on May 10. Shapovalov will overtake Raonic in the rankings as Canada's top tennis player for the first time on Monday.

Raonic is ranked No. 22 this week. His career high is No. 3.

The French Open begins May 27.

Raonic intends to return during the grass-court portion of the season. Wimbledon, where he lost in the 2016 final to Andy Murray, starts July 2.