Blues goalkeeper Colin Doyle has returned to Championship side Millwall on loan until the end of the season.
The young Irishman has so far spent three spells on loan with the south east London club and clocked up eight appearances for the Lions.
Doyle has impressed during his time in the Capital where he has helped Dave Tuttle's side move away from the foot of the table and harbour realisitic hopes of avoiding relegation.
But the 20-year-old now faces competition for the Lions keeper's jersey with fit-again Andy Marshall.
The 30-year-old former Norwich and Ipswich shot stopper returned to make his first appearance for over two months in the FA Cup draw with Everton and helped to keep the Toffeemen at bay with a string of fine saves.
"Colin has done a great job for us since he first came here, and I'm pleased that he's decided to stay until the end of April," said Millwall boss Tuttle.
"With Marshall now fit, we've got genuine competition for the goalkeeping position for the first time this season, which will hopefully bring the best out of both of them."
Doyle now comes into contention for Millwall's league visit to Preston North End this weekend, although Blues have not granted permission for him to play in Tuesday's FA Cup replay at Goodison Park.
His loan deal with the Lions runs up until April 30 - the final day of the Championship season - but Blues do have an instant recall option, although that can only be employed in exceptional circumstances.