Simplify the following text for a Grade 4 native English-speaking person.
Original: Mariano AndrÃ s PernÃ a Molina ( born 4 May 1977 ) is an Argentine-born Spanish footballer who plays for Club AtlÃ tico Tigre , as a left defender .
Simplified: Mariano PernÃ a ( born 4 May 1977 ) is a Spanish football player . He plays for AtlÃ tico Madrid .