PHILADELPHIA -- The Nationals wasted no time in making use of their latest acquisition, shortstop Anderson Hernandez. The 25-year-old was in the lineup Wednesday night against the Phillies, batting in the No. 8 slot.

"The first day, I am in the lineup," Hernandez said. "It feels good."

Hernandez came to the Nationals to complete Sunday's trade with the Mets in which reliever Luis Ayala was sent to New York. Hernandez occupies the roster spot left vacant by struggling utility man Kory Casto, who was optioned to Triple-A Columbus after Tuesday night's game.

Nats manager Manny Acta was quick to praise Hernandez's fielding. The shortstop was originally signed by the Tigers in 2001 and was labeled by Baseball America as being the best defensive infielder and having the best infield arm among players in Detroit's farm system in '04.

With the Mets, the young shortstop bounced around the big league club and New York's Minor League teams. Hernandez has struggled during his stints at the big league level, hitting a combined .138 (56-for-403). Still, his offensive numbers have been solid at the Minor League level -- Hernandez, a switch-hitter, is a lifetime .274 hitter with 155 stolen bases.

"He brings a lot to the table," Acta said. "He can run, too, which is another tool that he brings. He's a very useful guy for us."

Hernandez also gives Washington additional options in the infield, with Cristian Guzman nursing a sore left thumb. Guzman, the Nats' regular shortstop, has not played since Aug. 13. Acta said that Guzman looked good during a batting practice session Tuesday and was hopeful he would play Thursday.

Ronnie Belliard, who has been filling in for Guzman at short, is hitting .632 (12-for-19) in his past five games. Belliard shifted to first base for Wednesday night's game.