The Nigeria international, 32, will go straight into Wednesday's squad for their crunch derby clash with Barnsley at Hillsborough on Saturday.
Olofinjana is reunited with Dave Jones, who brought him to England from Norwegian side SK Brann in a £1.7million deal in 2004 when the Owls boss was in charge of Wolves.
Jones also signed Olofinjana on a season-long loan when he was manager at Cardiff during the 2010/11 season.
Olofinjana has struggled to hold down a place in Hull manager Steve Bruce's starting line-up this season, making 16 appearances.
He made more than 140 appearances during a four-year spell at Wolves and moved to Stoke for £3million in the summer of 2008, where he made only 14 starts, before Hull paid a similar fee for him in August 2010.