The Polish playmaker is to have a medical in Florence on Thursday, with the Viola on the verge of completing a hat-trick of January signings, as they bid to make a push for Europe
The deal, reportedly worth €2.8 million [£2.4m], will represent Vincenzo Montella's third signing of the window following the captures of Italy international striker Giuseppe Rossi and Argentine forward Marcelo Larrondo.
The 20-year-old midfielder will be tasked with supplying the ammunition to the Viola's new look front line as they set their sights on grabbing a European spot in the league.
"Rafal Wolski flies to Italy [on Wednesday] evening and will have medical tests tomorrow," Legia president Boguslaw Lesnodorski told the official club website.
"A deal with Fiorentina has not yet been signed, but the clubs are negotiating and are close to an agreement."
Fiorentina currently occupy fifth place in Serie A with 36 points.