Martinez has struggled to break through at West Ham and returned to the club this month.
The 21-year-old striker is in danger of leaving West Ham in the summer as his contract is set to expire at the end of the season, and he desperately needs to impress the Hammers in order to earn a new deal.
But that was only one of his two goals in 18 games for Rayo, and he returned to West Ham in a bid to engineer a second loan. This time, he has joined Rayo's La Liga 2 relegation rivals Lugo, as confirmed on his Instagram.
View this post on Instagram
It seems somewhat of a sideways move for ex-Valencia youth player Martinez, with Lugo sitting on the same points as Rayo - two places above them in 15th but only on goal difference.
Martinez was given his West Ham debut last season by David Moyes, but has the likes of Andy Carroll, Javier Hernandez, Marko Arnautovic and Lucas Perez above him in the pecking order.
Have something to tell us about this article?