The former Tottenham Hotspur striker has enjoyed two excellent seasons in the Netherlands, netting 30 Eredivisie goals and playing an influential role in their first KNVB Cup triumph in 13 years last term.
While also establishing himself as the focal point of Ireland's forward line at international level, the Hammers have earmarked the 24-year-old as their primary forward target who has an £18 million price tag.
Everton, Leeds United, Porto and Stuttgart are all reportedly interested in the striker whose AZ contract lasts until 2029, but West Ham are willing to meet the asking price, potentially making him the Sky Bet Championship's most expensive signing.
Loans from Spurs gain valuable experience
Born in Dublin, Troy Parrott joined Spurs in the summer of 2017 and was quickly identified as a long-term successor to Harry Kane.
He began in their youth ranks before signing on professional terms on his 17th birthday in February 2019, an indication of how highly rated he was in north London.
His Tottenham debut came nearly three years later in a 5-0 win over Burnley before extending his stay as he penned a new three-and-a-half-year contract.
Ahead of the 2020/21 campaign, Parrott embarked on the first of several loan spells away from the Tottenham Hotspur Stadium, making the move to Millwall.
However, he struggled for minutes so his season-long loan deal was cut short in order to sign for Ipswich Town where he made 18 appearances.
A successful stint at MK Dons followed, orchestrating their League Two play-off push with ten goals and seven assists, which led to Spurs again extending his deal in the summer of 2022 for a further three years.
His fourth loan spell in three years came with Preston North End and despite showing promising signs in 34 appearances, a knee injury prevented him from fully showcasing his true potential in Lancashire.
Move abroad proves vital for his development
All of Parrott's temporary moves had been within the Football League, but a move to the Eredivisie with Excelsior provided him with the perfect opportunity to kickstart his career overseas.
He did just that in a struggling side, netting 17 league goals yet wasn't able to save them from relegation.
Unsurprisingly, interest was rife in the Irish striker with the league's big-hitters eager to secure his signature and it was AZ who won the race in the summer of 2024 as Parrott permanently departed Spurs for £6.7 million.
He was an instant hit as he hit 20 goals across all competitions, including 4 UEFA Europa League goals as AZ reached the round of 16, before notching 16 in the league last term as they finished in seventh place.
This also sparked the best of his time on the international front as he asserted himself as Ireland's starting striker. He soon became a national hero by netting a hat-trick against Hungary to book their place in the play-offs for the FIFA World Cup, having scored a brace against Portugal only a few days prior.
A wanted man
Whether West Ham can land their target remains a big question with Championship football lacking the allure which top-flight sides possess.
The Hammers are particularly light in the forward department with Taty Castellanos and Niclas Fullkrug reportedly seeking a move away while Pablo has yet to hit the ground running since signing in January.
The arrival of Parrott would signal serious intent from West Ham as they aim to return to the Premier League at the first time of asking and a player whose goal-scoring exploits speak for themselves would go a long way to achieving that objective.
A return to London would certainly appeal to Parrott who would be front and centre of their promotion push.
Having only brought in one new face this summer in Keiber Lamadrid, West Ham are set to have a very busy end to the window as they aim to replace the key stars who have departed following relegation.