The 26-year-old, who has spent four years with Sporting Kansas City in the MLS, was granted a work permit in December and is eligible to play against Bournemouth on Saturday.
Espinoza is the fourth Honduran to sign for the humble north west club, following Wilson Palacios, Hendry Thomas and Maynor Figueroa, the latter who is still part of the squad.
"Usually players would have more time preparing for their debut and getting used to their new team mates, but Roger is so desperate to play as soon as he can that we hope to see him on the pitch on Saturday," Wigan manager Roberto Martinez told the club's website (www.wiganlatics.co.uk).
"He is an excellent talent and every time we have seen him play he has shown the desire that as a club we like to see from our players."
Espinoza, who went through the U.S. college system after moving to Denver as a 12-year-old, has been on Wigan's radar since the London Olympics when he impressed for Honduras.
"The Olympics in the summer gave a great example of just what he can do on the pitch, especially in his performances against Spain and Brazil," Martinez said. (Reporting by Martyn Herman, editing by Alan Baldwin)