Atletico Madrid on Tuesday announced that France forward Kevin Gameiro had sustained a muscle injury to his right thigh and that Spain forward Diego Costa had a bruised ankle, both sustained during the La Liga club's 3-0 win against Celta de Vigo.
Gameiro finished Sunday's clash with muscle problems, prompting an MRI scan on Monday, while Costa also had an MRI to evaluate the bruising to his ankle, after it was stomped on by Celta defender Sergi Gomez.
Atletico said Gameiro's scan confirmed he had had "a myofascial injury in the adductor muscle of the right thigh."
Gameiro and Costa missed Tuesday's training session at the Wanda Metropolitano stadium, and Solvenia goalkeeper Jan Oblak was also absent, practicing separately at the gym.
Atletico Madrid is to travel to Moscow on Tuesday for the UEFA Europa League round of 16 match against Lokomotiv Moscow, set for Thursday.