The Sporting Kansas City midfielder told Goal.com on Tuesday that he has agreed a two-and-a-half-year contract to join the Latics once his current deal expires on December 31 and is looking forward to making the move to the Premier League.
However, his new boss explained that there are a few hoops that need to be jumped through before the move can be officially sanctioned.
"There are a few steps, as you can imagine," Martinez told Sky Sports.
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Nevertheless, the 26-year-old's extensive international experience should ensure that there are no problems in gaining a work permit and Martinez is looking forward to seeing the player run out at the DW Stadium soon.
He continued: "Roger is someone that we have been following for a long, long time, someone that we have seen enjoying his football at the Olympic games recently with Honduras, and obviously at the World Cup as well.
"He has been an important part of that group of players with Maynor Figueroa and he will be a real asset for us."