Leeds tracked Lang throughout the summer transfer window, but Club Brugge were reluctant to sell a player they had only just signed on a permanent basis.
Whites director of football Victor Orta monitored Lang closely, but if the Yorkshire giants do choose to go back in for him in the future then they look set to face competition from two Premier League rivals.
The race for Lang is heating up and, according to Spanish outlet Fichajes, Arsenal, Leicester and AC Milan are all keen on the winger.
It is claimed that all three sides have Lang in their sights to reinforce their squad for next season.
It is unclear how willing Club Brugge will be to sell Lang next summer, but the winger penning a new deal will strengthen their hand.
The Belgian giants are likely to demand a steep price in order to let the winger go.
Lang has progressed immensely in Belgium and has started off this season impressively, scoring three times and registering four assists in his first four league games.