The Nigerian scored 18 goals in 39 league games last season to help the Timbers secure their first-ever MLS Cup title.
Adi, 25, joined the Timbers from FC Copenhagen in the summer of 2014 on an initial loan deal which later became permanent and has since established himself as one of the most feared strikers in MLS, netting a club-record 31 goals in 65 regular season appearances.
His form during his first 12 months in the USA proved somewhat erratic as he adjusted to the league’s arduous travel schedule, but the 6ft 4in front man found his feet over the second half of 2015 to prove instrumental in helping Portland win their first-ever MLS Cup title, finishing the campaign with 18 total goals in 39 games.
The towering Nigerian’s impressive performances even earned him his first senior international call-up in March, and there are now suggestions that he could be set for a move to Europe as soon as this summer.
Danish outlet BT reported during the winter transfer window that the likes of Celtic, Werder Bremen and Sporting Lisbon were all keeping close tabs on his progress, while Yahoo Sports now claim that Palace and St Etienne are also chasing the well-travelled striker’s signature after seeing him start the 2016 season with six goals in eight games.
The report also adds that Chinese Super League outfit Shanghai Shenhua are a potential suitor for the Timbers star, but it remains to be seen whether Adi would be interested in a move to Asia.
The fact he has yet to earn his first cap for Nigeria means there may be some potential work permit problems should Palace look to follow up their interest with a concrete bid this summer, but his performances in MLS over the last three seasons suggest he is still a target well worth pursuing.