WASHINGTON -- After watching his team defeat the Mets, 7-6, in 12 innings on Tuesday, Nationals manager Davey Johnson said he thought about having first baseman Adam LaRoche pitch had the game gone on to the 13th inning.

Johnson told LaRoche that he was going to pinch-hit for Ross Detwiler with Jhonatan Solano in the 12th inning.

LaRoche was a pitcher when he was in high school and college. The last time LaRoche pitched was for Double-A Greenville, a Braves affiliate, in 2003. During his pro career, LaRoche has pitched in two games, and picked up a victory while with for Class A Myrtle Beach.

"The one good thing was, I [asked] LaRoche, 'If I have to use Solano to tie the game, can you pitch for me?' He said he would be happy to," Johnson said. "I said, 'You are not going to hurt your arm?' He said, 'No, I won't be throwing that hard anyway.'"

After talking to Johnson, LaRoche went in the batting cage to warm up, but Johnson changed his mind. Detwiler ended up hitting for himself to load the bases.

"[Johnson] said, 'I have to let Det continue.' I said, 'OK, I appreciate you letting me get all excited there,'" LaRoche said. "I understand both sides of it. Obviously, I'm there if he needs me. I would love to go do it. But, on the other hand, I think [Johnson] made the right decision, and he helped us get a win."

Had LaRoche pitched, there was no way he was going to air it out. After all, he had shoulder issues last year.

"But I could give [the team] some strikes," LaRoche said.

Maldonado heads to DL; Moore recalled

WASHINGTON -- The Nationals were playing with 24 players on the roster on Wednesday because catcher Carlos Maldonado was still bothered by a sore back and was not able to hit. After the team's 5-3 victory over the Mets, the Nationals placed Maldonado on the disabled list and recalled first baseman Tyler Moore from Triple-A Syracuse.

This will be Moore's second stint with the club. He was 3-for-19 (.158) earlier this season.

As for Maldonado, he is the fourth catcher on the Nationals to suffer an injury, and third to go on the DL this year.

Wilson Ramos is out for the season because of a torn right ACL, while Sandy Leon has been sidelined with a high right ankle sprain. Jesus Flores was sidelined for almost a week because of a strained hamstring.

Mattheus takes positive step toward return

WASHINGTON -- Ryan Mattheus, who is on the disabled list because of a plantar fascia strain in his left foot, had a good bullpen session Wednesday and didn't have any discomfort. But, according to manager Davey Johnson, there is still some "puffiness" in the foot.

Johnson said Mattheus will have pitchers' fielding practice on Thursday and cover first base.

"His arm is in great shape. He doesn't have any problems throwing," Johnson said.

Mattheus was having a productive season before going on the DL, going 2-1 with a 2.25 ERA in 19 games.

Worth noting

• Outfielder Michael Morse is expected to be a designated hitter when the Nationals play the Red Sox at Fenway Park starting Friday. It will give Johnson an opportunity to play either Roger Bernadina or Rick Ankiel in the outfield. Both players have been benched because of the emergence of Bryce Harper and Steve Lombardozzi.

• Mark DeRosa is expected to start a rehab assignment either Thursday or Friday. He will most likely play for Class A Potomac. DeRosa has been on the disabled list because of a left oblique strain.