Sharapova, who beat Jennifer Brady in three sets in her first match in Stanford, has been forced to pull out of the tournament due to a left forearm issue. The injury will undoubtedly be extremely concerning for the five-time Grand Slam champion, who has just recovered from a thigh injury that saw her retire in Rome and then miss the whole of the grass court season.
Tsurenko, who was due to face Sharapova later today, has received a walkover and will face third seed Madison Keys or qualifier Caroline Dolehide in the last eight.
Injury troubles continue for returning Sharapova
It has undoubtedly been a difficult 18 months for Sharapova, after having a 15-month drugs ban for the use of Meldonium and now seemingly struggling to be 100 percent fit as she looks to return to the top of the game.
The Russian had struggled since her return due to a thigh injury, which eventually saw her miss two months of tennis, though she looked comfortable in both her first round win over Brady and when playing in World Team Tennis for the Orange County Breakers. During press conferences last week Sharapova claimed to be back to full fitness, though that is now evidently not the case.
What will be interesting to see now is whether she is able to recover for the rest of the hard court summer. Sharapova has received wildcards into both the Rogers Cup in Toronto and the Western and Southern Open in Cincinnati, and a place at the US Open is still available for the Russian; she is ranked high enough to be in the qualifying draw, or could well receive a wildcard into the final Grand Slam tournament of the year.