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It was confirmed Portugal international Joao Felix tested positive for the virus on 4 February, forcing him to miss two games for LaLiga's leader.
The first was a 2-2 draw at home to Celta Vigo, who netted a late equaliser, before Atleti beat Granada 2-1 in Andalusia on Sunday (AEDT) to stay five points clear at the summit with two games in hand on second-placed Real Madrid.
Moussa Dembele, Thomas Lemar and Hector Herrera were all confirmed as having the virus in the five days after Joao Felix's results were returned, but the situation has had minimal impact on the team's on-field performances.
Up next is a trip to Levante on Wednesday, before hosting Paco Lopez's men at the weekend, and that is followed by the first leg of their Champions League last-16 tie with Chelsea.
Simeone is unsure if Joao Felix will feature on Wednesday but was glad to have him back.
"He has not had many symptoms that left him unable to train at home, so he was working with the coaches since the fourth day [of his absence]," Simeone told reporters.
"He is eager and enthusiastic, he is healthy. It's great to be able to count on him tomorrow, but we will decide tomorrow what to do with him."
Attention soon turned to Atletico's other key attacker this term, Luis Suarez, who has recently been the subject of reports claiming the Uruguayan has a clause in his contract that would allow him to leave on a free transfer at the end of the season.
Simeone seemed unimpressed he was even asked the question.
"Normally I don't talk about personal contracts," Simeone said.
"I talk about how to attack, how to play, but I don't interfere in personal matters."