Ross Detwiler making the most of spot in the rotation

At one of the Washington Nationals’ minor league affiliates on Monday, right-hander Chien-Ming Wang will take the mound and begin a rehab assignment. Wang, who strained his left hamstring mid-way through spring training, will be allowed 30 days to make rehab starts before the Nationals have to add him to the active roster. They don’t anticipate him needing that long.

But with his replacement in the rotation pitching the way he is, the team may be faced with the prospect of delaying the sinkerballer’s return as long as they can —- if only to keep starting Ross Detwiler.

In six scoreless innings of work Friday night, Detwiler continued to reward the Nationals for their season’s-eve decision to put him in their starting rotation.

In the Nationals’ 2-0 victory over division foe Miami, Detwiler was dominant. He worked out of jams, got ground balls when he needed to and used his often overpowering stuff to generate seven strikeouts from a Marlins lineup chock-full of pop.

“Superb,” Nationals manager Davey Johnson called it, adding that he only pulled Detwiler after six innings and 79 pitches because the left-hander’s spring training was so abbreviated as a starting pitcher that he’s still protecting him and building him up.

“I’ll go further with you as we get a little longer into the season,” Johnson told a surprised Detwiler after the manager informed him he wouldn’t hit with his spot due up first in the bottom of the sixth.

But if Wang begins his rehab assignment Monday as planned, the Nationals will have to activate him by May 22, unless something goes awry in his recovery. Since he signed as a free agent this offseason, Wang cannot be traded until June 16, and he’d likely need some time showing he’s healthy and effective in the major leagues to draw any trade interest. Presumably, that means Detwiler’s days in the rotation are numbered.

The Nationals optioned John Lannan to Triple-A two days before the 2012 season began because they felt they were doing themselves a disservice by keeping Detwiler’s talent in a little-used role out of the bullpen. They couldn’t justify hiding him there then, but when Wang returns they might be forced to do just that

“I don’t want to think about it,” Johnson said, breaking into a wide smile after his No. 5 starter twirled another gem and lowered his season ERA to 0.56.

“I have to prove myself every time out because there’s somebody that’s great right behind me,” Detwiler acknowledged. “And once he’s healthy, then my job is to put it in their hands and make it a tough decision for them.”

In his first three starts, Detwiler has done exactly that. Even with the Marlins and Carlos Zambrano holding all but two of his teammates hitless, Detwiler’s performance was enough. And if not for Rick Ankiel, the Nationals would have likely wasted Detwiler’s gem.

The center fielder, whose season will hit its one-week mark Saturday, had the Nationals’ only two hits off Zambrano and was 3-for-3 by night’s end. He cranked a solo home run to center field in the third, then doubled and scored from third on an infield hit from Ian Desmond in the eighth. He also singled in the fifth.

The Marlins were also the second team in the last five days to hit a fly ball to center, but have their runner at third stand pat and not test Ankiel’s arm. Ankiel made a gamble of his own in the eighth to hustle into second on a ball to right field. The throw beat him there, but he slid his left arm back and reached out with his right to beat the tag.

With Ankiel moved to third on a ground out by Jesus Flores, Miami manager Ozzie Guillen opted to intentionally walk pinch hitter Chad Tracy to get a righty-righty matchup with Desmond.

“Make it hurt,” Johnson yelled to Desmond as the shortstop strode to the plate.

Desmond got just enough on Steve Cishek’s first pitch to push Reyes deep into the hole. His throw bounced out of Emilio Bonifacio’s glove at second and Ankiel came home.

“This is a big series,” Johnson said, alluding to the Nationals’ 47-78 record against the Marlins the last eight years. “We’ve had a history of not playing real good against Miami. Not that we thrashed them, but we hung right in there and beat them the first time out of the chute. We know we’re pretty good, we’ve just got to go prove it.”