Celtic have completed the signing of Paderborn midfielder Mika Baur in a £6.8m deal. The 22-year-old has completed a medical ahead of his move to the Scottish Premiership champions. Baur is now understood to be finalising the paperwork on a long-term contract at Celtic. The deal is reportedly worth around £4.5m upfront, with a further £2.3m in add-ons. A substantial portion of the bonuses is linked to Celtic reaching the Champions League league phase. This is Celtic's third signing of the transfer window, following the arrivals of Camilo Duran and Haissem Hassan. Speaking to club media after his unveiling, Hassan was clearly delighted to have confirmed the biggest move of his career to date. He said, “At 24, I think it's a good moment for me to move away from Spain. I've been there for six years. With Celtic's history, all the great players, the fans and the atmosphere, I think this is the perfect moment for me. "I know I'm joining a big club, the biggest club in Scotland, and I'm really looking forward to taking the next step.