Liverpool have signed central defender Steven Caulker on loan until the end of season from Championship side QPR.
The 24-year-old, capped once by England, was on loan at Southampton - but that agreement has been cancelled to allow him to move to Anfield.
He is eligible to face Arsenal in the Premier League on Wednesday.
Liverpool have been hit by a succession of injuries to central defenders and boss Jurgen Klopp said Caulker is the "best solution" for the club.
The 48-year-old German added: "We want to press the opponent and so they have to play long balls.
"If they play long balls, you need people in the last line who can help you with headers and we've found it with Steven Caulker."
Tiago Ilori was recalled from a loan spell at Aston Villa to play in the 2-2 FA Cup third-round draw at Exeter on Friday.
Caulker's last Southampton appearance came in the 6-1 League Cup defeat by Liverpool on 2 December.
"Steven came in in the summer before we signed Virgil van Dijk because we had long-term injuries and he was a back-up," said Saints boss Ronald Koeman.
"He didn't play a lot and normally we have more defenders for that position. I am not going to stop his opportunity to play for Liverpool."
Caulker, who won his one England cap in 2012, has seen his career stall after moving on loan to St Mary's Stadium after previously playing for Tottenham Hotspur and Cardiff City.
He also had loan spells at Yeovil Town, Bristol City and Swansea City during his time at White Hart Lane.
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