Chelsea face a transfer battle with French giants Paris Saint-Germain to sign one defender this summer. Mauricio Pochettino could ask for a new left-back to be signed when the window reopens. The Argentine does have Ben Chilwell, Levi Colwill and Marc Cucurella who can all play there. However, Chilwell has picked up more than one injury this season, while Colwill is a central defender by trade. It has also been claimed that Chelsea have offered Cucurella to Real Madrid, so his future at Stamford Bridge is far from certain. PSG tracking Chelsea targetIn an ideal world, Chilwell stays fit and Cu…