Douglas Costa will miss Brazil's World Cup game against Serbia on Wednesday with a thigh injury, team doctor Rodrigo Lasmar said.
Costa injured the thigh in Brazil's 2-0 victory over Costa Rica on Friday and, after scans, was ruled out for the Group E game in Moscow.
"Yesterday, at the end of the game, Douglas Costa complained of pain in the back of his right thigh, only remembering that he was injured, but in the left thigh," Lasmar said on Saturday. "It's been diagnosed as a small muscle injury, so he will not travel with us. He will stay in Sochi."
Costa, who was unavailable for training early in the World Cup camp, assisted Neymar's 97th-minute goal on Friday after replacing Willian at half-time.
Lasmar expects Costa him to return at some point during the World Cup, but his injury is more serious than that of Danilo, who injured his right thigh in training earlier this week and also will not travel to Moscow.
"Danilo's situation is not much different, but it's a less-important muscle, so the outlook is a little better," Lasmar said.
Neymar, meanwhile, is fit and has no lingering issues from the right ankle injury he sustained in Brazil's opener against Switzerland on June 17.
"Last week, everyone saw a move where he complained of a little pain and he left," Lasmar said. "From the first moment, we pointed out that it was a situation that had nothing to do with the problem for which he underwent surgery.
"As we had anticipated, he trained normally, went to the game. No complaints again on the foot, on the ankle. Fully recovered."
Even coach Tite was injured after falling while celebrating Brazil's first goal.
"We are in a situation where even the coach was injured," Lasmar said. "This is unheard of in my career. He had a small muscle injury in the thigh area, but nothing to worry about.
"He even said that his main job is to use his head. He started doing some work in physical therapy, recovery, but he's OK."