Borussia Dortmund winger Marco Reus is set for a spell on the sidelines after sustaining an ankle injury while on international duty.

The 25-year-old Germany international missed the World Cup after injuring the same left ankle in the team’s final warm-up match for the tournament against Armenia in June.

He is expected to be out of action for at least four weeks after sustaining the injury in the 2-1 Euro 2016 qualifying win against Scotland.

Reus will definitely miss Dortmund’s opening Champions League group match against Arsenal on 16th September. Borussia can be backed at 2.04 to win the match while the Gunners are 3.24 to make a winning start to their group campaign after knocking Besiktas out in last month’s two-legged play-off.

Reus will also miss the Bundesliga outfit’s second group game against Anderlecht on October 1.

“Team doctor Markus Braun on Monday diagnosed a partial tear and stretching of ligaments. The club expects the player to undergo a rehabilitation programme of four weeks,” Dortmund said in a statement.

Reus had only recently returned to action and appeared to be back to his best until he was injured in stoppage time against Gordon Strachan’s side. He is already a major doubt for Germany’s Euro 2016 qualifying double-header against Poland and Republic of Ireland in mid-October.

Reus was on the scoresheet on his last appearance for Dortmund when they recovered from losing to Bayer Leverkusen in their first Bundesliga game of the campaign to register a 3-2 victory at Augsburg.

Jurgen Klopp’s team are hoping to prevent Bayern Munich from completing a hat-trick of Bundesliga successes this season.