Koski is expected to be out for several weeks with a muscle injury in his right quadriceps suffered on international duty with Finland, according to Noticias de Alava.
Analysis:Koski had played every minute in LaLiga this season and was a key part of the defense, with one goal, four tackles, eight interceptions and 47 clearances in five league appearances, including the second most clearances in the league. His absence leaves Alaves thin at the back, already without Facundo Garces (knee). Nicolas Valentini is the most likely replacement after a strong showing at San Mames, with Xanet Olaiz another candidate, and a switch from a back five to a 4-4-2 is also possible depending on what coach Quique Sanchez Flores decides.
