Manchester United are set to re-enter the transfer market this summer for Paris Saint-Germain playmaker Javier Pastore as boss David Moyes looks to improve his squad.The Argentine attacking midfielder scored in the 3-1 first-leg Champions League win over Chelsea last week, but was unable to help his team from crashing out of the competition at Stamford Bridge on Wednesday.Pastore has had a difficult time since he arrived at PSG in 2011, failing to justify the huge fee the club paid Palermo for him.The 24-year-old is capable of moments of brilliance, but they have been few and far between at PSG.The French champions want more consistent performers to come in to build a team capable of winning the Champions League.According to Le 10 Sport, PSG are ready to let him go this summer and Manchester United are waiting in the wings.The future of Shinji Kagawa at Old Trafford remains in doubt, despite a recent upturn in form.The Japanese star is tipped to go back to Germany, which will open up a space for Pastore in Moyes’ team alongside Juan Mata.