American Varvara Lepchenko tested positive four times for meldonium, according to the International Tennis Federation, which cleared her because it was determined she took the substance before its ban went into effect on Jan. 1.
The ITF announced Tuesday that Lepchenko had been provisionally suspended in March but it was later determined that she "bore no fault or negligence for the violation."
Meldonium, also known as mildronate, is the same substance for which Maria Sharapova tested positive, drawing a two-year ban that she has appealed. She acknowledged taking the drug in January.
The Latvian-made drug is typically used for heart conditions.
The ITF said meldonium was in Lepchenko's system in decreasing amounts on Jan. 7, Feb. 1, March 1 and April 7. She appealed her provisional suspension, saying she had last taken mildronate tablets "on or around" Dec. 20.
The 30-year-old Lepchenko, who was born in Uzbekistan, is No. 79 in this week's WTA rankings.