With Mike Phillips likely to be missing for another three months after suffering ligament damage to the distal tib/fib joint, Jamie Nutbrown suffering from damaged posterior cruciate ligament and medial collateral ligament damage and Tom Isaacs ruled out for the season after a shoulder operation, Shane Williams has been left as the only possible scrum-half cover in their European squad.
Young scrum-half Rhys Webb is still making the first tentative steps back from a lengthy lay-off following shoulder and ACL reconstructions in the spring and is still some way from full fitness, forcing the Ospreys to look outside of the squad for cover.
Januarie, who has 40 caps for South Africa, will arrive at the region at the start of December, with his first Magners League appearance set to come against the Scarlets on Boxing Day.
Playing his rugby this year for Stormers in the Super 14 and Western Province in the Currie Cup, Januarie made his Springbok debut against Uruguay in June 2005, with his last cap coming as recently as September, when he featured off the bench in South Africa's 32-29 win in New Zealand.
He also featured in the first test against the British & Irish Lions in June, which finished 26-21 to South Africa.
Andrew Hore, explained:
"We have moved to secure Ricky's services because of the exceptional circumstances we face at scrum-half at this moment in time," said Ospreys' elite performance director Andrew Hore.
"December and January is a particularly tough period in the rugby calendar. It is make or break time in terms of European competition, and the possibility of securing a home quarter-final, and also, as far as our hopes of securing a top four position in the Magners League.
"The intensity of these games reaches almost test-match level with the Heineken Cup fixtures and a busy schedule of Welsh derbies, and it is clear that this is not the time to take risks.
"Ricky Januarie certainly fits the bill. He is a proven performer at the top level of the game, and he is really up for it. Having just missed out on the Springboks' European tour squad, he wants to come to Ospreylia and send out a message, before returning home to join up with the Stormers for the new Super 14 season.
"We are grateful to the WRU for their understanding of the current situation, and we look forward to Ricky joining the squad for training next week, ahead of the Viadana matches."