Anthony Joshua title fight with Kubrat Pulev in doubt

The IBF and WBA champion had been scheduled to face his mandatory challenger at Cardiff's Principality Stadium on October 28 and in front of a near-80,000-strong crowd, with over 70,000 tickets already sold.

Reports in Bulgaria claim Pulev suffered a muscle tear in training 10 days ago, and sources close to Joshua have refused to confirm the fight will proceed as planned.

According to Bulgarian newspaper Dnevnik, the 36-year-old Pulev requires a month to recover, has stopped sparring, and could yet face the champion in November or December.

The Principality Stadium is, however, in use on consecutive Saturdays from November 11 to December 2 for the Wales rugby team's autumn internationals, making an alternative opponent or postponement until 2018 a likelier outcome.

The expected crowd underneath the stadium's retractable roof was on course to set a new record for an indoor fight, which had stood since 63,315 witnessed Muhammad Ali fight Leon Spinks at the New Orleans Superdome in 1978.

When contacted by Press Association Sport, those close to Joshua refused to deny the development, though it is understood that an official statement will imminently be made.