Fiorentina must again do without Franck Ribery, but choose Christian Kouame with Dusan Vlahovic, while giant-killers Spezia start two ex-Viola forwards.
It kicks off at 17.30 GMT, you can follow the build-up and action as it happens from this game and Cagliari-Torino on the LIVEBLOG.
This is a relegation battle, but surprisingly Spezia in their first ever Serie A campaign are higher up the table right now than Fiorentina.
Ribery is out injured again, but Gaetano Castrovilli is benched in favour of Erick Pulgar and Giacomo Bonaventura, supporting Kouame and Vlahovic.
Siena are fresh from shock victories over Sassuolo and then-leaders Milan, with Vincenzo Italiano’s high-intensity football impressing new fans all over Europe.
He’s done it despite missing a lot of key players, including top scorer M’Bala Nzola, Diego Farias and Claudio Terzi, while today both defenders Simone Bastoni and Martin Erlic are suspended.
Today’s match is particularly intriguing, because ex-Fiorentina flops Riccardo Saponara and Kevin Agudelo both start in the trident attack, with Agudelo finding a new lease of life as a False 9.
Fiorentina: Dragowski; Milenkovic, Pezzella, Martinez Quarta; Venuti, Bonaventura, Pulgar, Amrabat, Biraghi; Kouame, Vlahovic
Spezia: Provedel; Vignali, Ismajli, Chabot; Marchizza; Estevez, Ricci, Maggiore; Gyasi, Agudelo, Saponara