Keane had signed a one-year loan deal with Preston but the 22-year-old asked van Gaal if he could prove himself in the Premier League.
The duo met on Tuesday and van Gaal eventually agreed to bring back Keane after he pleaded his case.
James Wilson is on loan at Brighton and Hove Albion and Keane should get a chance to prove himself with United’s options limited up top.
Keane, who was named United’s Young Player of the Year in 2010, has scored twice in 22 appearances for Preston. Supporters might have hoped for a more established star to feature up top for United following the January transfer window but it will be good to see Keane stake his claim for a place in the team.