Wolverhampton Wanderers have signed Diego Costa on a free transfer, the Premier League club said on Monday, with the former Chelsea and Atletico Madrid striker being parachuted in amid an ongoing injury crisis. Austrian striker Sasa Kalajdzic, Wolves' new 18 million euros ($18.24 million) recruit, sustained a knee ligament injury on his debut while Mexico forward Raul Jimenez was sidelined with a groin injury.