Maria Sharapova has pulled out of next week's Dubai Championships with an arm injury.

The 30-year-old struggled physically after her comeback from a 15-month doping ban last April, missing two and a half months with a thigh injury and then picking up an arm problem on her return in July.

Sharapova finished last season relatively strongly and began 2018 with a run to the semi-finals in Shenzhen before reaching the third round of the Australian Open, but she was beaten in the first round in Doha on Monday by Romania's Monica Niculescu.

The Russian, who is ranked 41st, had been awarded a wildcard into the tournament in Dubai, which she last played back in 2006. American world number 14 Madison Keys has also withdrawn through illness.