Roger Federer has pulled out of this week's Madrid Open due to a back injury.
The Swiss has been beset by injury problems this year, with Monday's announcement confirming his fifth withdrawal of 2016.
Following knee surgery, Federer had been scheduled to return in Miami, but was forced to pull out of that event with a stomach virus.
Federer made his comeback at the Monte Carlo Masters, where he was beaten in the quarter-finals by Jo-Wilfried Tsonga.
With the French Open three weeks away, there were concerns Federer could miss out at Roland Garros, but in a media conference on Monday the 17-time grand-slam champion indicated he would be fit to feature in Rome next week.