The Nigerian striker is becoming more and more frustrated as Fulham are yet to offer him a new long-term deal.
The 28-year-old impressed in his club's pre-season campaign, sparking interest from Championship side Reading.
However, Fulham have rejected several bids from the Royals, as boss Slavisa Jokanovic sees the forward as a key player for his side in the new season.
Aluko scored nine goals in 53 appearances for the Cottagers last year.
Fulham got their new campaign underway with a 0-0 draw against Leeds on Tuesday.