The Women's Tennis Association issued a formal warning to Anastasia Potapova for wearing a T-shirt of Russian soccer team Spartak Moscow before her match against Jessica Pegula at Indian Wells this week.
The Russian player's actions were viewed as a public show of support for her country during its invasion of Ukraine, and the 21-year-old was criticized by world No. 1 Iga Swiatek.
Potapova, when asked about the shirt after the match, said she had supported Spartak since she was 13 and saw no provocation in it.
"Regarding the Russian soccer team shirt, the WTA has formally warned the player that this was not acceptable nor an appropriate action," the WTA said in a statement. "We do not expect to see any reoccurrence of this in the future."
Ukraine's Lesia Tsurenko withdrew from her third-round match with Belarusian Aryna Sabalenka at Indian Wells due to what she said was a panic attack.
Tsurenko said the attack was triggered by a chat she had with WTA CEO Steve Simon about tennis' response to Russia's invasion, for which Belarus has been a key staging ground.
Russian and Belarusian players can compete on the WTA as individual athletes without national affiliation.