AC Milan chief executive Adriano Galliani has admitted it was a "quick decision" to sign Kevin Constant once news of Sulley Muntari's injury emerged.
The 25-year-old Guinea midfielder has signed from Genoa in a one-year loan deal, with the San Siro club having the option to make the move permanent next summer.
Milan moved fast after it was confirmed that Muntari will be out for around six months with an anterior cruciate ligament injury to his left knee.
"It has been a quick decision to take Constant and I must thank (Genoa) president (Enrico) Preziosi," Galliani told Gazzetta dello Sport.
"He was a player that we wanted to sign last year. In agreement with our coach, we have decided to get him once we found out about Muntari's injury.
"Muntari has had an ugly injury. I have never had a player that tore his cruciate during the holidays."
The Rossoneri have also confirmed they have acquired 50 per cent of the sporting rights of another Genoa player, defender Francesco Acerbi.
The 23-year-old, who spent last season at Chievo, has signed a five-year deal at Milan.
"To play at Milan is a dream come true for anyone," he said.
"I will try to earn a regular spot in the team. Playing alongside Thiago Silva will no doubt help me as he is the best defender in the world."