Former Chelsea defender Alex has urged his compatriot Marquinhos to leave Paris Saint-Germain, with the Blues and Manchester United apparently keen on the centre-back. According toSean Kearns of Metro, both of the Premier League giants have registered their interest in the 21-year-old. Alex, who now plays for Serie A side Milan, thinks Marquinhos should take one of these interested parties up on their offer if hes to realise his full potential, per L'Equipe (h/t Kearns):Marquinhos would fit in at any big European club. His problem is that two of the best players in the world in his position are ahead of him.If I was in his place I would leave PSGespecially when all the big clubs want him. During every transfer window, he gets magnificent offers. Hes young and should be playing to show his worth.A lack of playing time does seem to be an issue for Marquinhos. Hes only started three of PSGs Ligue 1 matches so far this season, with manager Laurent Blanc preferring the partnership of Thiago Silva and David Luiz.It leaves the French giants with three quality centre-back options, but for Marquinhos, being the deputy is not really befitting of his potential. As is evident here, the young Brazilian has the quality to go to the very top of the game:For Marquinhos, sitting on the bench has been a regular theme since he signed from Roma. The only times hes been able to get in the PSG team at centre-back is due to injuries or suspensions; otherwise, hes done a job for the Parisians in a right-back role. For a player who has so much talent, it must be a frustrating scenario.Despite his tender years,Marquinhos does have a lot to offer. As we can see here, courtesy of WhoScored.com, his distribution is of the highest order:Defensively, hes very sound, too. Marquinhos is an intelligent anticipator, is technical and tenacious in the tackle and is very quick across the ground. There are some areas in which he needs to improve, most notably his aerial ability, but for a player with an imposing physique, that would surely come with playing time.Whenever hes been in the starting lineup, PSG have looked a lot more solid. So the following statistic from OptaJean from last season shouldnt come as a great surprise:Chelsea are clearly on the hunt for a young centre-back after their much publicised pursuit of Evertons John Stones, per Sky Sports, and there are clear parallels to draw between the two. While they are similar in stature and style, unfortunately for the Blues, both players would most likely cost an extortionate amount, too.Alex is a player who knows what its like to play for PSG and Chelsea, so his thoughts on the matter are worth considering. Nevertheless, Marquinhos is still a young man, and while he may not be in the teams best XI, hell be learning plenty from the likes of Silva. Thatll ultimately aid his development moving forward, meaning its unlikely the French champions will be willing to cash in. Click here to read full news..