The answer: both.
Garner slotted in Burke as the No. 2 hitter, playing center field. Lamb played first base, hitting fifth. That meant Willy Taveras, who has started almost every game this season in center field, would sit out for the first time in the postseason.
Playing both Burke and Lamb gives Garner the luxury of utilizing his hottest postseason hitter and the player who has five hits in 12 at-bats off Cardinals starter Matt Morris.
Burke entered Saturday's game hitting .625 in the playoffs. logging five hits in eight at-bats. Lamb is 5-for-14 against Morris, and three of those hits were home runs.
"Lamb's numbers are good, and he is swinging the bat good," Garner said. "If Lamb wasn't swinging the bat good, I might not do it this way."
Taveras, the odd man out, was disappointed to not be playing Game 3 but handled the news well.
"They want to play [Burke], and he's been coming up big for us," Taveras said. "I'll be ready for whatever they want me to do. It's the manager's decision. It's whatever he thinks is best for the team. It's about winning -- it's the playoffs."
Said Garner: "This is just a today thing. I don't plan to do anything beyond today. When I talked to Willy, I told him he's playing great. We'll try this today. Burke's got a hot hand right now. Lamb's swinging the bat well, too. We'll give this a shot and see how it looks."
Burke, who started 73 games in left field during the regular season, made only one start in center. Coincidentally, that was the game that knocked him out of commission for a while when he dislocated his shoulder making a diving catch.
Burke said that mishap will not deter him from making another risky play if the situation arises.
"It's the playoffs," he said. "If a diving opportunity comes up, I'm going to take it."
More decisions: Garner briefly considered sitting Jason Lane in favor of Burke. Lane is hitting .200 in the postseason (4-for-20).
"He's had some tough games, but Lane's bounced back," Garner said. "We all have a game or two where we can look tough. They've pitched him tough, too. Anybody can look bad on any given day."
Garner also switched Adam Everett and Brad Ausmus at the bottom of the order. Everett hit eighth, Ausmus seventh.
On the mend: Andy Pettitte's knee was the size of a grapefruit after Game 1 of the NLCS, but in the three days since, the swelling has significantly decreased and the left-hander sees no reason why he would not be able to start Game 5 on Monday.
"The hard part was getting my leg up the day I pitched, because of the swelling," he said. "I was able to do that yesterday. I feel a lot better and there's no concern at all. I'll be fine for my start."
"I think you'll have to chain him down to not make that start," general manager Tim Purpura said.
Pettitte took a batted ball off the inside of his knee running the bases during batting practice prior to Game 1, and that injury likely was responsible for his subpar start against the Cardinals that night.
Since then, Pettitte has benefitted from regular treatments that helped eliminate the fluid that was filling up inside of his knee.
"It's spreading out nice, throughout my hamstring, my thigh, down to my calf," he said. "It's not concentrated there.
"The big thing is being able to heat it up. When you have a contusion like that, you can't put heat to it. You have to ice it. When you keep putting ice to something, it makes it extremely stiff. Once you get a little blood circulating there, it felt much better."
As much as he likes to take that first jog around the bases during batting practice, Pettitte said he'll probably chuck that tradition for the rest of this season.
"I guess I won't do it," Pettitte said. "They'll probably have a nervous breakdown if I do do it."
Alyson Footer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.