Chelsea striker Diego Costa has been excused from the start of pre-season training with the Premier League champions.

There is mounting speculation that the Spain international will return to former club Atletico Madrid after being told he is surplus to requirements by head coach Antonio Conte.

However, any move back to Atleti is complicated by a player registration ban for the LaLiga side, which means Costa would be unable to play for them before January.

Omnisport understands the 28-year-old is absent with Chelsea's permission after he was granted additional leave. There is no timeframe on his return.

Costa scored 20 goals in 35 league matches last term as Chelsea returned to the summit of English football but clashed with Conte during mid-season when links to Chinese Super League side Tianjin Quanjian briefly threatened to derail their title charge.

Conte's squad fly to Beijing next Monday for a three-game tour of China and Singapore.