The Egyptian striker, who returned from a loan spell at West Ham this summer, was left behind to work alone ahead of the new season.

"Mido isn't fit, so he's stayed behind to work on that," manager Gordon Strachan was quoted by Boro's official site.

Didier Digard, Andy Halliday and Jonathan Franks also missed the trip due to respective injuries.

Mido's fitness has usually been a setback for the 27-year-old, who has one year left in his contract with Boro.

Two seasons ago, he had to work on a special fitness program with Boro's ex-fitness coach Nick Allenby.