The summer signing won't be seen until the end of the year after suffering a knee injury earlier this preseason.
Brentford announced on Wednesday:
"Brentford’s Igor Thiago had successful surgery on Tuesday.
"Thiago suffered a meniscus injury during the Bees’ 5-2 victory over AFC Wimbledon on 20 July, which has been repaired. The striker will now begin a period of recovery and rehabilitation and is expected to return towards the end of the year.
"Thiago notched 18 goals in 34 Jupiler Pro League outings last term as Club Brugge won the title in what was his second full season in Europe, after scoring 15 in 32 in Bulgaria’s First League with Ludogorets.
"As well as those 18 league goals, he also grabbed four in the cup and notched seven times in Europe in a stellar first campaign that saw him named Conference League Young Player of the Season."