Tamara Korpatsch said on Instagram that she tested positive and withdrew from her next tournament in France.
It's at least the fourth known COVID-19 case among players who competed or planned to compete at the All England Club.
No. 8 Matteo Berrettini, the runner-up to Novak Djokovic a year ago, and No. 14 Marin Cilic withdrew before the tournament started. No. 17 Roberto Bautista Agut won his first-round match but pulled out Thursday.
Korpatsch lost to Heather Watson in their first-round singles match at Wimbledon.
She then criticized Tan after the French player withdrew from doubles to focus on singles.
Tan had just beaten Serena Williams in singles. She has continued her run, and has reached the fourth round.
Cristian Garin of Chile reached the fourth round at Wimbledon for the second straight year with a 6-2, 6-3, 1-6, 6-4 victory over 29th-seeded Jenson Brooksby of the United States.
The 26-year-old Garin will next face either 19th-seeded Alex de Minaur or wild-card entry Liam Broady for a place in the quarterfinals.
Garin, who is ranked 43rd, said he appreciated the chants from compatriots in the stands at No. 3 Court: "When I hear that, I know that the Chileans are (here) somewhere, so that's good."
The 21-year-old Brooksby was making his Wimbledon debut.
Harmony Tan beat Katie Boulter 6-1, 6-1 on No. 2 Court to reach the fourth round. It's the first time in her career that she has won three straight matches.
Tan, an unseeded Frenchwoman, beat Williams in three sets on Centre Court on the second day of the tournament. She then defeated 32nd-seeded Sara Sorribes Tormo in the second round.
Tan will next face either Coco Gauff or Amanda Anisimova in the fourth round.