Arsenal are on the verge of signing Sporting striker Viktor Gyokeres after negotiations over the finer details of the transfer took longer than expected.
BBC Sport reported last week a 73.5m euro (£63.5m) deal was in the final stages, with Arsenal hoping it would be done for the beginning of their pre-season tour of Asia, which starts on Sunday.
However, the move for the Sweden forward has been held up because of negotiations between the clubs over add-on payments.
Gyokeres has already agreed terms and a five-year contract with the Gunners.
The 27-year-old has been in demand during the summer transfer window after scoring 54 goals in 52 games for Sporting last season.
BBC Sport revealed earlier this month how Arsenal had turned their attentions to Gyokeres after hitting an impasse in their bid to sign Benjamin Sesko from RB Leipzig.
The search for a striker has been a drawn-out process for manager Mikel Arteta, who has been desperate to add an elite centre-forward after his side scored 17 fewer goals and finished 10 points behind champions Liverpool in the Premier League last season.
The Spaniard boosted his overall attacking options with the signing of England winger Noni Madueke, 23, from Chelsea last week.