Errani worked with Luis Garcia del Moral, one of the doctors at the heart of the Lance Armstrong doping scandal, but she parted ways with him in 2012, just months after she reached the French Open final, but before she reached her career high-ranking of No. 5 in 2013.
A urine sample that Errani provided on February 16 and was tested in Montreal contained letrozole, which is on the World Anti-Doping Agency's prohibited substances list, the ITF said in a statement. "There is no evidence I have intentionally violated the anti-doping rules; there is no evidence that Letrozole would enhance the performance of a female tennis player".
All her results between the two tests have been annulled, meaning she must forfeit ranking points and prize money accrued between these days. Errani argued that the drug usage was inadvertent and that her mum had been taking a drug that contained letrozole since she was first diagnosed with cancer in 2005.
Additionally, her results between February 16 (date of sample collection) and June 7 (date of her next test, which was negative) should be disqualified, the Independent Tribunal ruling on the case determined.
Errani reached the singles final at the French Open in 2012, losing to Russian Maria Sharapova 6-3, 6-2.
"I never took, in my life and during my career, any prohibited substance", the five-time major doubles champion said in a statement.
And subsequently, following a hearing last month, a suspension was imposed from 3 August and she will be eligible to compete again on 3 October.
Errani blamed contamination from her mother's breast cancer medication. "The only hypothesis is food contamination".
Errani's mother, Fulvia, appeared at a hearing between the ITF and her daughter, where she admitted to accidentally dropping Femara pills from her blister pack "onto the worktop or onto the floor" during the preparation of meals.
Errani and her mother also conducted tests to see how completely a pill could dissolve in food. Contamination was possible because there had been times when pills had been dropped or spilled.