Birmingham manager Alex McLeish told the Premier League club's official website that it makes sense for the forward to get some action in the Championship.
"Going up there for two months is an opportunity for him," said McLeish.
"When it's time for him to come back, we hope he'll be in great form and pushing for a place in the team.
"He's obviously had one or two setbacks with injuries. But he's a big, strong centre-forward with pace and presence - and when he's on top form he's an asset."
Middlesbro' 4/9, Draw 3/1, Plymouth 7/1