Martinez told the Wigan Evening Post: "Technically Ben is a wonderful footballer, very gifted, and he played very well for Queens Park Rangers during the first half of the season.
"We just felt he needs to carry on playing football to maintain his match sharpness. And by going to WBA, he will be able to do that.
"We can call him back after 28 days if we want to – it's not a case of him going there and not seeing him until the end of the season.
"He is going there to help keep up his own intensity, and we'll be able to call him back when he reaches the level that we feel he would be ready to play for us."