The 25-year-old joined the Hornets as a free agent but is being eased back to full fitness having not played a competitive game since February.
“Myron is a good striker,” Dionisi said. “It’s important that he’s at 100 per cent.
“I spoke to my staff and, probably before the international break, Myron will be part of the team.”
Jeremy Ngakia and Jack Grieves have both returned to group training as they recover from hamstring and knee injuries respectively, while Branimir Mlačić is expected back with the squad next week.
Edoardo Bove, however, will remain sidelined until at least October having suffered a ligament injury in his right knee against West Brom.
Kwadwo Baah and Marc Bola are also progressing with their rehabilitation, while Travis Akomeah continues to work on the pitch with the rehab coach.
Martín Payero is a doubt for Watford’s next game after reporting pain in his right adductor against Preston and is being assessed.
Dionisi’s squad has, however, been bolstered by the signing of former West Ham striker Michail Antonio.
The 36-year-old has signed a one-year deal with the club.
“It’s a good set of boys here,” Antonio said. “They are focused and ready to show their abilities this season.
“Watford is a big club and hopefully I can come in and bring success and help wherever I can.
“I’ve scored a few goals against Watford! So hopefully I can score some for Watford now when I’m fully up to speed.”
