"It's been that way for a couple of days," Griffey said of his sore muscle. "I think I just jammed it sliding. It may have [been the catcher's] shin guard."
Griffey had to suddenly accelerate during the play. He originally thought Dunn's hit was a ground-rule double until he saw third-base coach Mark Berry waving him around.
"I thought somebody touched the ball after [Dunn] hit it," Griffey said. "I said, 'OK, he's got a double.'"
Cardinals starter Sidney Ponson certainly caught a bit of a break. Griffey was 6-for-11 with three homers lifetime against Ponson.
It's been a spectacular road trip for Griffey, who has hits in all eight games he's started --including six multi-hit games. During the stretch, he's batting .471 (16-for-34) with four homers and eight RBIs. That included a two-homer game Monday, where he hit the game-winning three-run shot in the ninth inning.
Griffey missed a month earlier this season with a sore tendon in his right knee. Batting .298 with 10 homers and 34 RBIs for the season, he has seven homers and 20 RBIs over his last 16 games.
Reds manager Jerry Narron said the 36-year-old Griffey was listed as day-to-day.
"He'll probably be fine," Narron said. "He'll either get [Thursday] night off or Sunday night."
It wouldn't be a shock if Griffey missed Thursday's game since the Cubs were scheduled to start Glendon Rusch, a left-handed pitcher.
As expected, third baseman Edwin Encarnacion was also missing from Wednesday's lineup. Encarnacion suffered a mild left ankle sprain in the fifth inning Tuesday when forced to abruptly stop while running the bases. He spent several moments on the ground before he left the game to get X-rays, which were negative.
"It shouldn't take him too long to be ready to go," Narron said. "After the way he appeared, I thought it was something really, really serious."
Rich Aurilia started at third base for Encarnacion, and went 4-for-5 with five RBIs, including a sixth-inning three-run homer in the 7-4 win.
LaRue starts, Ross sits:
Another hot bat was out of the Cincinnati lineup, but not for health reasons. Catcher David Ross, who is batting .339 this season and on a 10-game hitting streak, was rested in favor of Jason LaRue.
"I just thought it'd be better to give him [Wednesday off] instead of [Thursday] night with [Bronson] Arroyo pitching," Narron said. "LaRue has done a pretty good job with Aaron Harang. I'm very, very pleased with the way David Ross is playing."
LaRue has struggled lately, but finally ended an 0-for-29 slump with a soft seventh-inning single into short left field. He is batting .174 for the season.
Double-A Chattanooga outfielder Noochie Varner and Class A Dayton pitcher Johnny Cueto were named the Reds' Minor League Player and Pitcher of the Month, respectively, for May. Varner batted .404 with six homers and 34 RBIs last month. Cueto was 3-0 with a 2.45 ERA while opponents batted just .152.
By the numbers: According to the Elias Sports Bureau, Tuesday's 7-0 win was only the fourth time in the last 60 years a Reds team posted a shutout victory on the road against the team with the best record in the National League. The last time it happened was a 16-0 win at Atlanta on June 18, 1994.
Arroyo (7-2, 2.40 ERA) gets another crack at Rusch when the Reds open a four-game home series against the Cubs Thursday at 7:10 p.m. ET. Arroyo hit a home run against Rusch in his each of their two previous meetings this season.