The 19-year-old right-hander, whose birthday is Sunday, was placed on the seven-day disabled list with what manager Dave Machemer said was "a problem with a fingernail" on his throwing hand.
Before being placed on the disabled list Sunday, Wheeler was scheduled to start Monday but was scratched over the weekend in favor of right-hander Kyle Vazquez .
On the same day as Wheeler's move off the active roster, reliever Jose Casilla was removed from the disabled list and put back onto the list of available arms in the bullpen.
Machemer said he wasn't sure when Wheeler will make his next start. Since beginning the season with three rocky outings, Wheeler hasn't allowed an earned run in three of his past four starts.
Wheeler has a 1-3 mark with a 5.03 earned run average in seven starts this season. He's 1-1 with a 3.95 ERA in his past four outings.
CALLING ALL ARMS: For the second consecutive weekend, the GreenJackets needed more than 41/2 hours to complete a game.
Almost a week after knocking off Savannah in an 18-inning contest that took four hours and 35 minutes May 16, the GreenJackets needed 15 innings to put away Greenville on Saturday night.
The 8-6 victory took four hours and 43 minutes, making it Augusta's longest game of the season.
Seven GreenJackets pitchers were used. Though some managers will call on a position player to pitch in a long, extra-inning game, Machemer said he's hesitant to pull such a move. Former GreenJacket infielder Mike Loberg injured his elbow while on the mound in the final game of the season last year.
"If I did (put a position player in to pitch), it would be a last resort kind of thing," Machemer said. "You don't want to see someone get hurt."
Machemer said switch-hitting right fielder Daniel Cook , who throws right-handed, and infielder Juan Martinez , another right-hander, have offered to take the mound if necessary.
OFFENSIVE TRIP: The GreenJackets' pitching staff got much of the credit for a four-game sweep of Savannah in the team's last home stand -- allowing one run in 45 innings -- but the Augusta bats did the trick during the team's most recent road trip.
The GreenJackets won three of four games at Greenville with an average of 11 hits per game and more than five runs per game.
Center fielder Evan Crawford and left fielder Nick Liles led the charge with three multihit games each. Crawford drove in four runs, scored four more runs and walked eight times in the four-game series. Liles went 7 for 15 with three RBI in the final three games.
The GreenJackets entered Monday's game with nine wins in their past 10 games, with only one home run.
HOME SWEET HOME: Entering their eight-game home stand, the GreenJackets owned a piece of the top home record in the South Atlantic League at 14-6, with seven consecutive victories at Lake Olmstead Stadium. The Savannah Sand Gnats were also 14-6 in their ballpark.
The GreenJackets were tied for first in the league with a road record of 14-10.