The 26-year-old did not travel with United’s initial squad to the United States due to being given an extended holiday as Mexico reached the last-16 stage of the World Cup.
Hernandez's future at Old Trafford remains uncertain however, as he started just six times in the Premier League league last term and refused to confirm he will stay at the club when asked at the end of the season.
Robin van Persie, who scored four goals at the World Cup as Netherlands secured third place ahead of Brazil, has been given a three-week holiday by Louis van Gaal, while Belgium duo Marouane Fellaini and Adnan Januzaj are also set to join up with United's squad later this summer.
Anderson has not travelled with the squad due to a calf injury, while Bebe is also absent as he closes in on a move to Benfica.
United play LA Galaxy in their first pre-season fixture on July 23 before facing Roma on July 26, Inter on July 29 and Real Madrid on August 2 in the International Champions Cup.