Barcelona, Atletico Madrid and AC Milan keen on Chelsea striker Pierre-Emerick Aubameyang | OneFootball

Barcelona, Atletico Madrid and AC Milan are monitoring Chelsea striker Pierre-Emerick Aubameyang, reports the Daily Mail.

The Gabonese was left out of the Blues’ squad for the knockout stage of the Champions League.

Manager Graham Potter also dropped January signings Noni Madueke, Benoit Badiashile and David Datro Fofana.

Aubameyang joined Chelsea during the last summer transfer window from Barca. The Spanish club were keen on bringing the 33-year-old back to Camp Nou last month.

However, Financial Fair Play concerns made it impossible, with La Liga insisting Barca would not be able to register him.

The Blues striker also could not join Atletico or Milan despite their interests.

FIFA rules prevent a player from appearing for more than two clubs in a single season.

Aubameyang played eight minutes in a La Liga game earlier this term before sealing the move to Stamford Bridge.

The trio plan to return for his services in the summer.

He is out of favour under Potter and was allowed to travel abroad after he was omitted from last night’s matchday squad against Fulham.

The former Borussia Dortmund star has started just four out of the 11 Premier League games he has played this term.

He has scored just a league goal, with two goals and two assists to his name in six Champions League games.

Aubameyang shone at Barca last season, with his 11 league goals helping them to a top-four finish.

He scored 22 league goals in each of his first two seasons at Arsenal.

Unfortunately, he has struggled to replicate that form at Chelsea and a summer exit appears to be on the cards.