This led to negotiations on a payment structure for the release clause and a breakthrough was achieved on Friday evening.
Personal terms were discussed with the midfielder's representatives at the start of the week and were never considered an issue.
Szaboszlai's talent and attitude as well as the Hungarian's apparent comfort in playing in midfield have been appreciated.
The club are also exploring a number of options as they look to increase technical quality, mobility and depth in midfield.
Inter Milan midfielder Nicolo Barella is also a target but he is leaning towards staying at the San Siro amid strong interest from a number of Premier League clubs.
Background work has also been done on Bayern Munich's Ryan Gravenburch and Nice's Khefren Thuram.