Union bolster defense with Costa Rican left back

The Philadelphia Union continue to revamp their roster ahead of the 2012 season. A day after adding midfielder Gabriel Gomez, the club announced on Thursday the acquisition of Costa Rican left back Porfirio Lopez.

The terms of the agreement were not disclosed.

Lopez, 26, joins Philadelphia from Chinese club Dalian Haichang, where he has been on the books since 2010. After one season in China, however, Lopez went on loan with Costa Rican club Alajuelense, where he won both the Clausura and Apertura titles in 2011.

Lopez gives manager Peter Nowak a new option at left back, a position that was in flux for much of last year. Gabriel Farfan and Jordan Harvey, who was traded midseason, both saw time there.