When asked how excited he was to be playing his old club first, Hernandez told West Ham's official website: "I think a little bit more than my team-mates probably. West Ham and the national team are the only teams I care about this season".
Such was his impact, West Ham gave the France global an improved contract in February of that season that made him the club's highest-paid player on £125,000 a week.
The Hammers have put their early summer struggles behind them to secure Joe Hart, Marko Arnautovic and Javier Hernandez in quick succession, and along with free agent Pablo Zabaleta the squad now looks a lot healthier heading into the new Premier League campaign.
"I was desperate to come back to the best league in the world".
The Red Devils take on West Ham in their opening EPL match of the new season on Aug 13.
And Hernandez, when asked about returning to Old Trafford, was unable to hide his excitement at the prospect of playing in the Premier League again.
Arnautovic said: "To the fans I was let's say the hero and now I am zero".
"But no doubt that for West Ham to get a player with his experience and his quality is very, very good". "He is a fantastic player, very experienced.he has bene everywhere he has scored goals for Manchester United, then he scored goals for Real Madrid and Bayer Leverkusen".
During a press conference on Tuesday, Mourinho was asked whether he had given any thought to entering the race for Hernandez's signature and he explained why he didn't even consider it. Overall, his time in Germany saw him score 28 goals in 54 league appearances.
West Ham are now on a pre-season tour of Germany where Hernandez is expected to join the rest of the squad this week.
"The one thing I can say is, I am happy to be here and happy to play for West Ham".
West Ham have since longed for a goal scorer and will hope Chicharito can do the job with Andy Caroll regularly injured and Sakho failing to impress.