BBC Sport revealed at the start of the month how Arsenal had turned their attentions to Gyokeres after hitting an impasse in their bid to sign Benjamin Sesko from RB Leipzig.
Gunners sporting director Andrea Berta flew to Lisbon towards the end of last week to lead negotiations with Sporting.
This weekend, Sporting’s president Frederico Varandas said Gyokeres was facing disciplinary action after failing to report for pre-season training.
Gyokeres, who scored 54 goals in 52 games last season, has yet to publicly explain why he has not turned up for pre-season.
Varandas told Portuguese news agency Lusa that “no one is above the interests of the club”.
Former Brighton and Coventry striker Gyokeres has scored 97 goals in 102 matches during his two seasons in Portugal, firing Sporting to two league titles.
