Alejandro Garnacho has been told that facets of his game are not at a good enough level for a big club like Chelsea or Manchester United. The 21-year-old swapped Old Trafford for Stamford Bridge this summer and despite showing flashes of quality for Enzo Maresca's team so far, some of his detractors still feel there are some glaring holes in his game. Former United winger Lee Sharpe believes that the Argentina international's decision-making is just not good enough. While he praised his technical ability, athleticism, and X-factor capabilities, he still needs to improve a great deal to become a more complete player.He told Adventure Gamers: "It’s always the same with Alejandro Garnacho. His issue is, and has always been, his decision-making in the final third. Skill-wise, pace-wise wise and his ability to excite people is second to none. But sometimes, he tries to shoot when he should pass and vice versa – he can get stuck in little areas, and it’s probably not quite at the level you need at a big club like Manchester United or Chelsea. Whether that is something that improves with age and experience, I don’t know. He has been in the Premier League for several years now and you would expect him to have developed in those areas, but I don’t think he has."Garnacho was once seen as one of Argentina's most exciting rising stars but he has been frozen out of the country's national team for nearly a year. Incidentally, former Argentine international Oscar Ruggeri thinks the youngster needs a bit of a reality check.He said: "He's no better than anyone else, you're a football player, enjoy it, but you shouldn't be so full of yourself. It's pointless because you miss out on so much. Someone has to bring him down to earth. They're not calling him up to the national team. If he comes back down to earth like he was, they'll call him up again because he's phenomenal on the pitch."Indeed, former United defender Paul Parker feels the way he left the Red Devils, and the way he carried himself in his final few months there, were unprofessional.He added: "His conduct on and off the pitch was disrespectful. All he wanted to do was score a goal or have a near miss so he could act like Ronaldo. Now he's gone to a club where there’s a lot more ego. He will alienate himself or it’ll be a battle there. United fans backed him when he was going through things both on and off the field. His brother was tweeting things and they backed him and he said nothing. He’s stuck two fingers up at the club that nursed him."This year, Garnacho has come under heavy fire from pundits for his antics but Chelsea head coach Maresca believes in the young winger.After his goal in the Blues' 2-2 draw with Qarabag in the Champions League in midweek, the Italian said: "Now, when you don't win, I can understand that it's always, but I think Garnacho, he has done well in the second half. We gave him the chance. He's slowly, slowly improving."With Garnacho not having to worry about playing for Argentina this month, the ex-United ace will hope to start for Chelsea at home to Premier League basement side Wolves on Saturday night. If results go their way, they could move into the top four by the end of the weekend.