Atletico Madrid welcome Diego Costa back to training; Borussia Dortmund's Paco Alcacer a doubt

Atletico Madrid coach Diego Simeone says he hopes to have Diego Costa back fit again to start their top-of-the-table Champions League clash at Borussia Dortmund on Wednesday, as his strength and energy lift everyone around the team.

Former Chelsea striker Costa scored in Atletico's opening-game win away at Monaco and set up a goal in the 3-1 victory at home to Club Brugge, was then sidelined since hurting his hamstring against the latter on Oct. 3, but has travelled to Germany ahead of the return to UCL action.

"[Costa] gives us physical strength and energy," Simeone told the pre-game news conference in Dortmund. "He is important for the character that he transmits. He has been out, so we will see if he starts or not. He wants to get back, and when we have him it lifts the fans, his teammates and us in the coaching staff."

Montenegro centre-back Stefan Savic has also returned to the squad after six weeks out with a muscle injury, and could come straight back into the XI, as fellow defender Jose Maria Gimenez has missed the trip with a sciatic nerve issue.

Dortmund lead the group on goal difference after beating Brugge 1-0 away and Monaco 3-0 at home and are also top of the Bundesliga, having thrashed Stuttgart 4-0 on Saturday, while Atletico were held to a 1-1 draw at Villarreal.

"They are a strong side, and for a long time nobody but Bayern has been leading the Bundesliga," said Simeone. "They are at their best at the moment. We will have to play with intelligence. Their transitions from defence and midfield are very good. Their defenders and midfielders are good on the ball. We will aim to do what we have been doing these seven years, to play to our strengths."

Meanwhile, Dortmund may have to do without their main striker Paco Alcacer.

The 25-year-old, who is leading the Bundesliga with seven goals, did not partake in the team's final training on Tuesday afternoon.

Head coach Lucien Favre also confirmed at his news conference earlier that day that he will have to do without the injured left-back Marcel Schmelzer and centre-back Manuel Akanji.

This will be just the third meeting between the sides, having previously met in the group stage of the 1996-97 Champions League.

Reuters contributed to this report.