Diego Pablo Simeone said he is hoping to recover the best version of Antoine Griemann ahead of their Champions League Group B opener against Porto on Wednesday.
The French international joined Atletico Madrid from FC Barcelona but he was far from impressive on his first match as 'Colchonero' in La Liga.
Key defender Kieran Trippier left training early due to a stomach problem and there is no word yet on whether he will be fit to play on Wednesday.
Head coach Diego Simeone will be looking to translate his side's domestic dominance into international success as Atletico chase their first-ever Champions League title.
The 2021-22 season marks Atletico's ninth consecutive appearance in the group stages of the Champions League, but they have failed to make it past the last 16 in three of the past four seasons.
English side Liverpool and Italian giants AC Milan complete Champions League Group B.