Vincenzo Italiano is expected to keep Fiorentina in the same shape as their last three games, from which La Viola have picked up three wins from four matches.
Pietro Terracciano will start in goal, while the back four four of Dodo, Nikola Milenkovic, Igor and Cristiano Biraghi is expected to stay the same as it was in the 1-1 draw with Spezia in Serie A on Saturday.
Sofyan Amrabat could come in to replace Gaetano Castrovilli and partner Rolando Mandragora in the midfield double pivot.
Nicolas Gonzalez has been tipped to be given an opportunity from the start on one wing, with Josip Brekalo likely to start on the other side of the pitch.
Giacomo Bonaventura is likely to start again behind Arthur Cabral, who also keeps his starting spot in the Fiorentina team.
Kick off in Poland is at 20.00 UK time.
Lech Poznan (4-2-3-1): Bednarek; Pereira, Salamon, Milic, Rebocho; Kvekveskiri, Karlstrom; Marchwinsk, Afonso Sousa, Skoras; Ishak. Allenatore: Van den Brom.
Fiorentina (4-2-3-1): Terracciano; Dodo, Milenkovic, Igor, Biraghi; Amrabat, Mandragora; Gonzalez, Bonaventura, Brekalo; Cabral.