Man in the middle: Colorado Rapids midfielder Martin Rivero was acquired by Chivas USA today (Photo courtesy Chivas USA).

Chivas USA have signed their fourth Argentine player, Colorado midfielder Martin Rivero,who made 30 appearances for the Rapids in 2012 and led the team in assists.

A right foot fracture suffered in preseason limited his appearances for Colorado in 2013 and the club opted not to bring him back this year.

“Martin is a very talented player who already knows the league,” said Chivas USA coach Wilmer Cabrera.  “His personality, technical ability and energy will help us a lot. He is a hard and relentless worker on the field, always looking to gain and maintain possession, an area we need to improve. Once settled, he will blend in well with our current players and make us a better team.”

Rivero, 24, who also made more than 50 appearances for Argentine club Rosario Central, joins Mauro Rosales, Leandro Barrera and Agustin Pelletieri on the Chivas USA roster and is available for Saturday’s game against the Timbers in Portland.

Chivas USA has also waived two fringe players: midfielder Daniel Fragoso, 31,  a Spaniard who was only signed by the club last month and defender Andrew Ribeiro, 23, who has yet to make his MLS debut.