DORTMUND, Germany (AP) — Borussia Dortmund's newly signed forward, Henrikh Mkhitaryan, will be out for four weeks after injuring his ankle in a friendly.

The Bundesliga club says Mkhitaryan twisted his right ankle and partially tore a tendon shortly after scoring the third goal in Dortmund's 4-1 win over FC Luzern in a friendly in Switzerland on Tuesday.

Mkhitaryan has scored in both friendlies since joining Dortmund. The Armenia international completed his transfer from Shakhtar Donetsk last week and signed a four-year deal.

He was signed to replace Mario Goetze, who moved to Bayern Munich, which beat Dortmund in the Champions League final.

Mkhitaryan could miss the Bundesliga season-opener on Aug. 10 against Augsburg.