Real Madrid have announced an agreement to sign highly-rated teenage defender Jesus Vallejo from Real Zaragoza.
Aston Villa have continued their spending spree after securing the services of Rudy Gestede from Blackburn on a five-year contract.
Siena have appointed former Sampdoria boss Giuseppe Iachini as their new head coach after dismissing Serse Cosmi on Sunday night.
The Bianconeri parted company with Cosmi following a 4-1 defeat at Tuscan rivals Fiorentina that left the side propping up the Serie A table, and 48-year-old Iachini is the man charged with reversing the club's fortunes.
Speaking to acsiena.it, Iachini said: "I promise to bring hard work and determination to achieve the objective of surviving in Serie A.
"If there is one main reason why I came here then it is because I believe in the ability of these boys.
"I thank the club for putting their faith in me and I hope to repay them every day with my commitment as we build our road to salvation brick by brick."
Iachini replaced Gianluca Atzori at Sampdoria in November last year, steering the Ligurians back to Serie A through the play-offs, but promptly losing his job to ex-Juventus boss Ciro Ferrara, who was also sacked on Monday.
Siena president Massimo Mezzaroma told the club's official website: "I took the decision to make a change on the bench after the defeat in Florence, because I firmly believe in the players and the possibility of salvation.
"I think Iachini has the incentive and the ability to get it right.
"I thank his predecessors for their work but I am convinced that we must now start again with even more determination to realise our dream."
Siena remain bottom of the league table despite picking up 17 points so far, a tally that would have seen them sit in 14th place if not for the six-point deduction applied for their alleged involvement in the summer's betting scandal.
The Bianconeri's performances have faltered over recent weeks, though, with yesterday's heavy loss marking a third consecutive reverse to leave Siena with just two wins from their last 12 games.
Iachini's first game in charge sees third-placed Napoli visit the Stadio Artemio Franchi, with Siena four points shy of 17th-placed Palermo and safety.