Perez is the first left-handed reliever to come off the board this winter, with options like Tony Sipp, Antonio Bastardo, Matt Thornton, Jerry Blevins, Randy Choate, Brian Duensing, Eric O'Flaherty and Manny Parra still being available on a strong market. Thornton, who pitched for Washington last season, will likely head elsewhere after the team's addition of Perez.
Perez joins Felipe Rivero and Matt Grace as lefties in the Nationals' bullpen, and will likely see significant time as a middle reliever. Nick Lee may also be in the mix for a bullpen job with Washington.
Perez, 34, was traded from the Diamondbacks to the Astros in August and struggled to a 6.75 ERA in 22 appearances with Houston down the stretch. He is a veteran of thirteen major-league seasons with the Padres (2002-03), Pirates (2003-06), Mets (2006-10), Mariners (2012-13), Diamondbacks (2014-15) and Astros (2015).