Arsenal boss Arsene Wenger has completed the signing of veteran goalkeeper Jens Lehmann on a rolling monthly contract until the end of the season.
Wenger, who originally signed Lehmann from Borussia Dortmund in 2003, was desperate to bring in goalkeeping cover with Wojciech Szczesny, Lukasz Fabianski and Vito Mannone on the sidelines.
Manuel Almunia is Arsenal's only fit senior goalkeeper and the Gunners had 19-year-old James Shea on the bench for Saturday's FA Cup quarter-final defeat at Manchester United.
However, after deciding to come out of retirement Lehmann has been training with the club and will be available to take his place on the bench for the weekend's game against West Bromwich Albion.
Wenger said: "Jens Lehmann is a great short-term signing for us and will be a valuable asset during a crucial time of the season. Jens has kept himself very fit during this season and will provide quality back-up to Manuel Almunia. Jens knows the club very well, is vastly experienced and will also be an extremely positive influence in the dressing room during his time with us."
The German, 41, made almost 200 appearances for Arsenal before returning to the Bundesliga with Stuttgart in 2008 and then retiring last summer.
Lehmann said: "I'm very excited to be rejoining Arsenal. I have kept myself fit since the end of last season and I'm ready to contribute at any time for the team. I have many great memories from my previous time at the club and Arsenal has always had a place in my heart. It's special to be coming back. I can't wait to start working with the team again and I look forward to contributing as much as I can, both on and off the pitch during this time."
Arsenal have plenty of injury worries, with centre-half Thomas Vermaelen not expected to play again this season following his recovery from an Achilles problem, while Johan Djourou is set for around six weeks out with a dislocated shoulder.