The World Cup winner is leaving the coaching staff at the Emirates to focus on his role as television pundit.
Warburton took his Rangers squad on a 10-day trip to the USA and is delighted with the results.
The Scottish Premiership side take on Lincoln Red Imps on Tuesday.
Sunderland are currently on tour of Austria, as Sam Allardyce's side step up their preparations for the upcoming campaign.
Ibrox side Glasgow Rangers are on the hunt for two more additions this summer.
Newcastle United have signed Isaac Hayden on a five year deal from Arsenal.
Aston Villa are on the hunt for a new addition up-front, following their relegation to the Championship.
Watching Ben Simmons pass a basketball is something you could do all day. At 6ft 10in, he towers over the other point guards, flicking throws to team-mates that blur in the arena lights. It is easy to see how he can be that rare generational player who will lead the Philadelphia 76ers for the next decade.
Championship boss Garry Monk signed Eder for Swansea City last summer, a deal which led to his downfall.
The Italian marksman left Southampton for a Chinese move on Monday.