"You have now examples already of clubs investing and making important movements in the market and we are still nine matches away from the end of the season," he told reporters on Thursday.
"But would I expect us not to do anything and to stay exactly with the same squad that we have in this moment? My answer is no," he was quoted as saying by the BBC. British media said Chelsea triggered a 50 million euros release clause to get the Germany international. Manchester United in January splashed out 55 million euros on Sporting's Portugal midfielder Bruno Fernandes.