The 26-year-old is set to join his compatriot Maynor Figueroa at DW Stadium upon the expiration of his contract, which is new that has delighted Latics boss Roberto Martinez.
"We prepared an excellent case for Roger, and it is great news for us that he can now join up in January," Martinez told the club's official website. "He is a player we have been following closely since June 16, 2010, when he made his debut in the World Cup versus Chile.
"In that game, he showed tremendous potential and slowly he has been developing into an exciting footballer over the last three seasons in the MLS and has enjoyed terrific experiences at international level, specifically his role with Honduras in the Olympic games.
"The games versus Spain and Brazil in that tournament showed the winning and strong mentality that he possesses, which will be an important asset to our squad."
Espinoza will leave MLS after five seasons in Kansas City and is reported to have signed a two-and-a-half-year deal with the Latics.
"This has been a dream for me to play in England and I am so grateful for the club who have worked so hard to make this happen," Espinoza said. "I just can't wait now to join up with Maynor and all the guys and get to work."