Chelsea's efforts to sign DouglasCosta from Shakhtar Donetsk in the summer have been deal a cruel blow as Barcelonahave entered the race to bring him to Spain.

The Brazilianinternational has had another very good season in Ukraine and helped his teamto the last 16 of the UEFA Champions League before being knocked out by BayernMunich, yesterday evening.

He has had a very successfulspell with Shakhtar, winning the Ukrainian league five seasons in a row, butthey are struggling to retain it this year with Dynamo Kiev leading the waypresently, and are seven points clear at the top.

He is an attacking midfielderfull of creativity and flair and possesses similar traits to what Chelseaalready have in Oscar, Willian and Hazard. Costa has two Brazil caps to hisname and he is rated in the region of £22 million, and at the age of24-years-old he is good value.

The key issuesthat face Chelsea are that Barcelona have identified him as a future successorto Andrés Iniesta, and are willing to match his price. Also, José Mourinho'smen already have a host of talent in his position and their fans in particular,may be hoping they look for a striker in the summer to rotate with Diego Costa.

With Didier Drogbaset to retire and Loic Remy also a suspected outgoing player in the summer,they are going to be lacking depth in that department.

With Cesc Fàbregas, JuanCuadrado, Ramires and the three player’s aforementioned players, The Blues haveseveral players capable of playing in his position. Also they have MohamedSalah in their ranks, who is impressing on loan at Fiorentina so maybe a movefor Douglas Costa does not fit and may prove to be insufficient business.

Mourinho could behaving a clear-out in the summer and looking to bring in new blood as they lookto refresh for next season's Champions League campaign after this one ended indefeat to Paris Saint-Germain last night.

Whether Chelsea do go throughwith the deal is to be questioned in the coming months, but they have certainlybeen tracking their man for a long time are still tracking his progression.