He wanted to remind them to continue playing hard and that there is "still light at the end of the tunnel." Riggleman also wanted to find a way to motivate his team to keep pushing, despite being well back in the National League East standings.
Whatever he said worked, as the Nationals came out firing on all cylinders in their 4-2 win against the D-backs on Friday night.
One person who must have listened to Riggleman intensely was lefty John Lannan. Despite having an up-and-down season, Lannan (4-5) had a stellar performance against Arizona in the series opener.
He picked up his second consecutive win after allowing two runs on four hits with five strikeouts in seven innings. Lannan, who appears to be turning his season around, has allowed two earned runs or fewer in his past three outings.
Riggleman said it was one of the best starts he has seen out of Lannan this season.
"It's right up there," Riggleman said. "He had a good changeup and threw some good breaking pitches to the left-handed hitters. Overall he pitched very well, and it's a tough, aggressive hitting ballclub with a lot of power and the wind was blowing out. Good job."
Lannan's only blemish came in the fourth inning with the Nationals leading, 4-0. After walking Mark Reynolds with one out, Lannan gave up an RBI triple to Stephen Drew. Gerardo Parra followed with an run-scoring single to center field to cut the Nationals' lead to two.
The well-pitched start was a breath of fresh air for Lannan, who was sent down to Double-A Harrisburg in late June to fix his mechanics and build his confidence before coming back to Washington in early August.
"I just feel good out there," Lannan said. "I feel confident with my stuff. I spent time down [in Double-A] trying to get my two-seam [fastball] back, getting in good position to hide my ball more and being more deceptive. It still is going to get better.
"I'm running into some trouble in some of those innings, but I just got to keep the damage to a minimum and build off each start."
Reynolds said he noticed a change in Lannan from the last time he faced him.
"Normally he leaves a lot of hittable balls over the plate, and today he was hitting the corners pretty good and kept us off-balance with his changeup and his cutter," Reynolds said. "Besides the one inning, we weren't able to string things together."
Lannan was replaced in the eighth inning by lefty reliever Sean Burnett, who did just as good of a job. He earned the save after striking out four in two perfect innings.
Burnett said he tried to relax out on the mound and not focus too much on mechanics.
"I've just got to go out there and let the athletic ability take over," Burnett said. "I was able to throw a good sinker and the slider was working, too. It was just one of those nights where everything was clicking."
And while Lannan and Burnett were sharp on Friday night, so were Washington's hitters.
With Alberto Gonzalez and Ian Desmond on second and third base with one out in the first, Ryan Zimmerman hit a two-run single off starter Joe Saunders to left field. Two batters later, Michael Morse hit an RBI single to make it 3-0 in favor of the Nationals.
Wil Nieves added to Washington's total with a solo home run to center field in the second inning. Nieves, who is known primarily for his defense, was glad he could contribute with the bat.
"I just put a good swing on it," Nieves said. "The guys make fun of me, but I told them I have occasional power. I don't have the Adam Dunn swing; I'm a line-drive hitter. But I can hit it pretty far once in a while."
Greg Rosenstein is an associate reporter for MLB.com This story was not subject to the approval of Major League Baseball or its clubs.