Dortmund's Sebastien Haller to miss Atletico clash but Jadon Sancho to return
Dortmund trail 2-1 after the first leg in Madrid, with Haller scoring a goal late to bring the visitors back into the tie.
Haller was subbed off after just 10 minutes in Dortmund's 2-1 win over Borussia Monchengladbach on Saturday, the Ivory Coast striker's first league start since September.
Terzic said Haller "needs to rest for a week to get a clearer diagnosis but we assume he'll definitely be unavailable for two to three weeks."
The injury continues Haller's health struggles at Dortmund. The striker missed six months with testicular cancer after signing with the club in the summer of 2022.
This season, he missed several matches with an ankle injury after returning from winning the Africa Cup of Nations with Ivory Coast.
Dortmund were however given a boost with the news that England winger Sancho, who missed Saturday's win over Gladbach completely, will return.
"Jadon is fit again. He immediately felt better on Sunday and could train yesterday. He's back in the squad."
Terzic would not reveal whether Germany striker Niclas Fullkrug or teenager Youssoufa Moukoko would replace Haller up front.
"We've got two training sessions and a bit of time to go. We had three players in that position and now we have two.
"In the past we've played well with Fuellkrug up front, in the past we've played well with Moukoko up front - and we've done well with both on the field."