But really, who can blame him?
"I'm having fun," said Volquez, the NL's ERA leader. "It's the All-Star Game. You can't be nervous. You're here to enjoy the All-Star Game."
There was more to that smile than meets the eye, however. Part of it was no doubt a byproduct of two days packed with festivities, which for Volquez included a Red Carpet Parade down the streets of Manhattan and a front-row seat to the Josh Hamilton Home Run Derby show at Yankee Stadium.
"Unbelievable," Volquez called Hamilton afterward.
Don't forget it was Hamilton who was on the other end of the Texas-Cincinnati trade that landed the 25-year-old hurler in a Reds uniform back in December.
Part of it was that ring -- which he called the highlight of his visit to New York City. Yes, it came before both the Derby, the parade and even the game. In fact, it was the first thing Volquez pulled out postgame when the cameras started rolling.
But part of it was also a reflection of where he's been, where he is and where he's going.
"The last two years, I was struggling a little bit," Volquez said. "I have made the adjustments to make the All-Star team."
That smile would be temporarily wiped off Volquez's face, however, when his first All-Star appearance ended on a less-than-desirable note. Sent out to protect a 2-0 NL lead in the seventh, Volquez immediately surrendered a leadoff double to Minnesota's Justin Morneau.
Morneau advanced to third when Volquez induced a groundout. The Cincinnati right-hander then came back with a beautiful 95-mph tailing fastball to Tampa Bay catcher Dioner Navarro to record the second out of the inning.
But a 2-1 hanging fastball to Boston's J.D. Drew would land in the right-field seats, erasing a slim NL lead and making Volquez the first NL pitcher to give up a run on Tuesday. The home run came in Drew's first All-Star at-bat.
"When you come to the mound and see like 60,000 people, it's amazing," Volquez said afterward. "I had to face a hitter like him, and it's a challenge. I threw one bad pitch."
But Volquez responded by coming back to strikeout Texas' Michael Young to end his 18-pitch inning and to finish off an otherwise incredible few days.
"I think that's what I am going to keep in my mind," he said. "Those strikeouts."
For a pitcher who was pitching in Class A a year ago and at risk of losing his top-prospect label, on Tuesday night the results could all be put aside. This was simply about the experience.
"I just wanted to be here and have fun," Volquez said. "It's been great since this is my first full season in the Major Leagues, especially since this game is the last All-Star Game at Yankee Stadium. That was unbelievable."