Lidge has not thrown since last Saturday, when he blew a save by allowing two runs to the Marlins, his second blown save of the year. Lidge, 35, took over the closing role with Rodriguez after Drew Storen underwent surgery to remove a bone chip from his elbow. Lidge has allowed four earned runs in seven innings this year.
The Nationals acquired Perry, 25, in a trade this winter when they sent Collin Balester to the Tigers. A 2008 first-round draft pick, Perry has a career 4.07 ERA in 161 1/3 innings for the Tigers over three seasons. At Syracuse this season, Perry, who throws his fastball in the high-90s, has allowed two earned runs in nine innings with 11 strikeouts and four walks.
Rodriguez has mostly dominated, throwing 100-mph fastballs while mixing in a diving changeup and biting curve. He has yet to allow an earned run in 8 1/3 innings while striking out 10.
Meanwhile, the Nationals have made some changes to their lineup:
M. Ellis, 2b
AJ Ellis, c