Andy Murray has withdrawn from next week's Swiss Indoors tournament in Basel with a back injury.
The world number three was forced to pull out of last year's event with a right gluteal strain.
The 25-year-old Scot has played tournaments in Tokyo and Shanghai in the past two weeks, losing the final of the latter to Novak Djokovic.
Murray had been seeded second for the Swiss Indoors, which starts on Tuesday.