"I guess it was just an awkward swing on a slider," Gattis said. "I was trying to check the swing, and it just grabbed me on my right oblique."
Gattis continued to handle his defensive responsibilities while catching during the eighth and ninth innings. But he was not going to bat if Freddie Freeman had not ended the game with his walk-off home run off Dillon Gee in the ninth inning.
Brian McCann was in the on-deck circle, preparing to pinch-hit for Gattis until Freeman homered.
"I didn't think I could hit again," Gattis said. "Catching, I was loose and warm with adrenaline and everything going, and I just didn't think I could swing again."
Based on the way he felt Tuesday morning, Gattis was happy he did not attempt to push himself and cause even more damage to his oblique.
"I was a lot more sore today," Gattis said.
Gattis is batting .252 with 14 home runs, 37 RBIs and a .894 OPS in 53 games. The 26-year-old rookie served as Atlanta's starting catcher until McCann returned from offseason shoulder surgery on May 6. Over the past month, Gattis has served as McCann's primary backup and established himself as one of the game's most feared pinch-hitters.
Gattis has gone 6-for-8 with four home runs, one double and two walks in 10 pinch-hit plate appearances. But he's recorded just one hit in the 25 at-bats he's had while in the starting lineup, dating back to May 31.
Gattis' only previous experience with an oblique strain occurred during the final week of the 2011 season with Class A Rome. He's hoping this ailment does not sideline him for more than two weeks, and he'll be eligible for activation on July 3.
"I hope to just do whatever I can to get out there as soon as I can," Gattis said.
Gerald Laird will be McCann's primary backup while Gattis is sidelined. Laird has received very limited playing time while serving as Atlanta's third catcher for most of the past month. His start in the first game of Tuesday's doubleheader was just his fourth since May 15.
Pastornicky hit .309 with four home runs and a .780 OPS in 57 games with Gwinnett. The Braves could give him an occasional start at second base, but he'll likely be primarily used as a pinch-hitter over the next couple of weeks.
Pastornicky was informed of his promotion around 2:30 a.m. ET. He caught a 6:15 a.m. flight from Buffalo to Atlanta and arrived at Turner Field approximately two hours before the start of the first game of Tuesday's doubleheader.
"I know I can hit here," Pastornicky said. "I've proven I can hit here, so it's just getting up here, being comfortable and going out there and playing."