Clippard and Capps have come through most of the time for the Nationals, who are a surprising 20-18 entering Monday's action against the Cardinals.
Besides being among the National League leaders in holds with seven, Clippard is tied for the Major League lead in wins, also with seven. Capps has clearly been the best closer in baseball so far, allowing two earned runs in 19 1/3 innings while leading the Major Leagues with 14 saves.
"They have been outstanding," Riggleman said. "One of them is leading the league in wins and one is leading the league in saves. They are shutting ballgames down for us."
Clippard and Capps have been so good that Washington, D.C., native Steve Repsher gave them the nickname "Clip-n-Save," which has stuck among Nationals fans and sports journalists around the nation's capital.
Asked how he feels about the nickname, Clippard said, "It's kind of catchy, I guess. I told Capps we need to open up a gas station in Washington. It sounds like a gas station. It's cool, I guess."
Capps loves the nickname, but gave Clippard most of the credit.
"It's cool to have the recognition," Capps said. "You can't say enough [about] what Tyler has done. It seems like he is on the mound every day and getting the job done. It has been fun to watch him go about it. If I go out and put up three outs before the opponents tie the score before the ninth inning, that's a good thing. It's on me."
No one expected Clippard and Capps to have the impact they have had on the team now. Entering last season, Clippard wasn't positive about being a reliever. He thought he would be in the rotation for Triple-A Syracuse, but his then-pitching coach Steve McCatty -- now the Nationals' pitching coach -- and former manager Tim Foli had other plans for him.
Near the end of Spring Training, McCatty informed Clippard that he was going to be a reliever to start the season. The reason for the switch was that Clippard threw too many pitches as a starter and didn't have good fastball command.
Foli and McCatty believed Clippard would be better as a reliever because he wouldn't have any problems facing hitters the first time through the order.
"I felt if he gets behind, he can use his offspeed pitches [in relief]," McCatty said. "He has a resilient arm and good velocity on his fastball. We wanted to see how it went."
How did Clippard feel about the switch? He thought the Nationals were giving up on him. Clippard then called his father, Bob, who told his son to be thankful that he was still in baseball.
"There were a lot of questions that were going through my mind when it happened," Clippard said. "I called my dad and told him they moved me to the bullpen. There was a pause for a little bit, and he said, 'That's good, man. You still have a job. You were put in professional baseball, and not too many people in this world have that opportunity.'
"That was great to hear from him. You don't really know how other people in your life are going to take that news. I was on the fence about it. It was good hear it."
Clippard has since prospered as a reliever and now believes he could be a closer in the future.
"It doesn't matter where I'm pitching. I feel like I can get it done and I think every pitcher will say that," Clippard said. "If you have a uniform on and you have confidence in what you are able to do, I don't think it matters what inning you are pitching in. Everybody is going to feel confident in what they [can] do."
There were people who wondered if Capps still had the confidence to be a closer. Last December, Capps was non-tendered by the Pirates after saving 27 games while posting a 5.80 ERA in the 2009 season. Even worse, Capps didn't have a good Spring Training for the Nationals, giving up 10 runs in 11 2/3 innings.
Capps said he was trying to get his arm in shape during the exhibition season.
"There are a lot of guys whose numbers are terrible in Spring Training," he said. "Spring Training is a time to get your body in shape and, especially for pitchers, your arm in shape. You want to build up to the point where you can throw every day or every other day. A lot of times, especially the first couple of weeks, the results part of it is on the back burner.
"Last year was what it was. It was a bad year for me. I feel like there were a lot of positives I could walk away from. The save opportunities were pretty good, but that's not every aspect of my game. There were games I came in with the game tied. I wasn't good in those situations last year."
When the regular season started, Capps showed that his arm was in great shape. So much so that he was named Major League Baseball Delivery Man of the Month for April.
Capps finished the month with a Major League-best 10 saves, converting each of his save opportunities in 12 games pitched. Capps, 26, posted a 0.68 ERA, struck out 15 batters and held opposing hitters to a .226 batting average in his first month with the Nationals.
Capps' dominance has continued during the month of May, as he's allowed one run in six innings.
"I'm throwing strikes and getting ahead of guys," Capps said. "I'm following the game plan that [catchers] Pudge [Rodriguez] and Wil [Nieves] have put in place. I just follow the game plan well, hitting my spots and making my pitches at the right time."
Don't tell Capps that he's having a great year. It's the middle of May, he said. Talk to him in October about the 2010 season.
"It's still very early," Capps said. "If we were having this conversation in September, then I will say, 'Yeah, it has been a good year.' If we keep playing the way we are playing, keep giving ourselves an opportunity to win every night, I think it can be a good year." .
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.