Raonic cancels practice due to back spasms ahead of Round 2 match

There could be some trouble in store for No. 10 Milos Raonic ahead of his second-round match at the US Open against Fernando Verdasco, with multiple reports claiming he cancelled his Tuesday practice due to back spasms.

If serious, the ailment could spell the end of a very disappointing Grand Slam season for the Canadian, whose quarterfinal berth in Melbourne currently stands as his best major result in 2015.

Raonic looked to be approaching his breakthrough among the top tier of players after a semifinal appearance at Wimbledon last year, but injuries have stalled his progress. Foot surgery kept him out of play at Roland Garros, and he was knocked out in Round 3 by Nick Kyrgios at the All England Club.

Raonic won his first-round match Monday, beating Tim Smyczek in straight sets. He is 3-3 in six career matches against Verdasco.