And now, according to Sky Sources, Arnautovic has ironed out personal terms with the East London club, and is currently undergoing a medical.
Hernandez, who struggled to nail down a regular spot in the side at Manchester United, has had success in Germany at the BayArena, while continuing to kick on with Mexico at global level.
Arnautovic, who has signed a five-year deal, is set to become West ham's highest-ever earner with a £100,000-a-week deal agreed.
During his time at Old Trafford he scored 59 goals in 156 appearances - many of those from the bench. Bilic tended to use a 3-4-2-1 formation last season, and given Carroll's injury woes, Hernandez can be confident of lining up on August 13 at his former club Manchester United as the focal point of the attack. As with Ayew, who joined the Welsh club a year earlier on a free transfer, the fee for Arnautovic represents a significant profit for Stoke.
He has netted 39 times in 76 matches for the German club.
Things are looking up, and West Ham fans should be optimistic about the forthcoming season if these signings all happen. It's also on par with other play makers like Liverpool's Sadio Mane and new West Ham teammate Manuel Lanzini.
He will need to improve because he's going to be the record signing, and the West Ham fans, they won't take anything.
In a transfer market where an unprecedented amount of money is being spent on strikers, West Ham have stolen the show with a bargain of a signing.