The Dutch midfielder has been locked in talks with Galatasaray over a potential move to Istanbul this weekend after Inter accepted a reported 10million euro bid for his services.
Reports in Italy suggest Inter will use the money from his transfer to fund a swoop for highly-rated Corinthians midfielder Paulinho.
Sneijder has not featured for the Nerazzurri since September having rejected a proposed two million euro pay cut, with Moratti just as eager to bring the uncomfortable stand-off to an end.
He told the Gazzetta dello Sport on Monday: "It would be professional if he would make his decision by the end of the day."
In the absence of an anticipated approach from a Premier League side, with Manchester United having been heavily linked with the player in 2011, Galatasaray soon emerged as Sneijder's most likely destination when the Turkish giants became the first club to make their interest public.
On Saturday, a statement published on Gala's official website read: "The transfer of Wesley Sneijder has been agreed between Inter and the club, and negotiations are ongoing with the player."
The Super Lig leaders return from a winter break for Friday's game at Kasimpasa, while Inter attempt to narrow Juventus' lead at the top of the Serie A table.
A 2-0 victory over Pescara at the weekend saw the Nerazzurri close to within seven points of Antonio Conte's Juve, but Sneijder made just five appearances at the start of the season before suffering a leg injury against Chievo.
Rumours of a contract dispute were confirmed when Sneijder - who won the treble under Jose Mourinho - failed to return to the first team on his recovery, later revealing he would not agree reduced terms on a five-year contract he signed in 2010.
Inter head coach Andrea Stramaccioni has maintained the 28-year-old's ongoing omission is a tactical choice, despite a serious injury crisis that has seen up to 10 senior players sidelined throughout the autumn.