Vincenzo Montella explained that Marco Storari's experience was the reason AC Milan signed the 40-year-old goalkeeper until the end of the season.
Storari, who previously spent time at Milan from 2007 to 2010, re-joined the club from Cagliari on Tuesday, with shot-stopper Gabriel going the other way on loan until the end of June.
Veteran Storari left Juventus for Cagliari in July 2015 having won four Serie A titles playing as second choice to Gianluigi Buffon in Turin.
And he will now serve as deputy to Milan's teenage keeper Gianluigi Donnarumma.
"I have known Storari for a long time, we wanted to send Gabriel out on loan to play and then we learned of this possibility," coach Montella said at a media conference.
"Marco knows the environment and can be important both on and off the field. He knows what it means to play for AC Milan and I am sure that his experience will come in handy."
Milan are fifth in Serie A as they chase a return to Champions League football, two points behind third-placed Napoli and nine adrift of leaders Juve.