Before Wednesday's game against the Phillies, Acta asked Lopez about playing the position and Lopez agreed to take a chance. Lopez was later seen with an outfielder's glove and practicing in left field. Lopez would bring additional speed to the lineup.
"He is a very good athlete," Acta said. "We have approached him about it. He has a great attitude. He has no problem with it. It will be good for him to get those at-bats."
Lopez said he can play any position because he is an athlete. He planned to call former Reds teammate Adam Dunn on Wednesday night for some pointers on how to play the position.
"If you can play shortstop, you can play anywhere," Lopez said after the Nationals' 1-0 victory over the Phillies. "I can do it. As long as I get at-bats, I catch the ball."
The move means that Willie Harris will go back to the bench. Harris played the past two games because of his versatility and the fact that he works the pitch count.
"Our tendency at this point is to go with what we have [in the Major Leagues] right now, but there are other options if that's not working out," Nationals general manager Jim Bowden said. "This is a guy who always had good jumps and angles on the baseball."
Of the two players on the disabled list, Pena, who has a strained left oblique, is getting better quicker than expected. He is talking dry swings and hitting off a batting tee.
Dukes, on the other hand, has a Grade 2 right hamstring strain, and Bowden said he expects Dukes to be out longer than expected.
"Because it's a Grade 2 hamstring, it's very important that we get that to be 100 percent before he comes back to this club. We don't want another setback," Bowden said. "We are going to go overboard on this hamstring. I've had too much experience with hamstrings if you bring him back too early."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.