The 29-year-old Paraguay striker, who was signed from Rovers by Mark Hughes in July, 2009, has been unable to force his way into Roberto Mancini’s team this season after recovering from injury.
“Rocky”, who featured in the World Cup in South Africa last summer, has started only one match this campaign, in the Carling Cup at West Brom in September, and Mancini recognised his need for regular football.
He returns to the club where he made his name as a prolific Premier League scorer after joining Hughes at Ewood Park from Bayern Munich, but his time with the Blues has been blighted by injury setbacks.
Abdisalam Ibrahim is also on the move as the 20-year-old midfielder goes on loan for a month to Scunthorpe, against whom he made his senior debut almost a year ago in a fourth-round FA Cup tie at Glanford Park.
Abdi signed for the Championship club in time to make his Scunthorpe debut tomorrow against Leeds at Elland Road.