For the better part of a month now, the Nationals have been forced to talk about the impact they'd experience from the losses of several key players due to injury: Bryce Harper, Stephen Strasburg, Ross Detwiler, Wilson Ramos, Ryan Mattheus. Well, for the first time in a month, they finally get to talk about the impact one of those players' return will have on the club's fortunes: Jayson Werth. Having successfully completed a five-game rehab stint with Class A Potomac, Werth is scheduled to come off the disabled list Tuesday and be in the Nationals' lineup for their series opener against the Mets. And not a moment too soon for a club that could desperately use the veteran outfielder's contributions, especially at the plate after he went 9-for-17 with two homers on his rehab assignment. "That'll be a shot in the arm," manager Davey Johnson said following yesterday's loss to the Braves. "He must've been really feeling frisky. He'll be ready to carry us on his shoulders, I'm sure." Whoa, let's not get too excited here. Werth will have a positive effect, but the odds of him carrying the Nationals on his shoulders seem remote. What Werth will bring to the table, though, are two things the Nationals have sorely been lacking since he last played May 2 before a strained hamstring sidelined him: 1) Professional at-bats with an emphasis on reaching base, and 2) Reliable defense in right field. How much have the Nationals struggled to put men on base? Well, their team OBP following yesterday's game fell to .287. That's not only the lowest mark in the majors at the moment, it would rank among the five worst marks in baseball since 1969.