Hazle played a big role in helping the Braves win the pennant when CFer Billy Bruton went down with an an injury. According to Retrosheet, Bruton's last game that year was July 11. At the close of play that day, the Braves were in a virtual tie for 2nd with the Phillies with the Cardinals in first.
His entire major league experience before this was going 3 for 13 in 1955 with the Reds. Click here to see his Baseball Reference page
Hazle's first game was July 29. He had just a sacrifice bunt as a pinch hitter in the 5th inning, and the Braves did not score in that inning. They did win the game 9-8 in extra innings.
His next game was July 31. He started in RF. At the close of play on July 30, the Braves were now already in first place, with a half game lead over the Cards. The Dodgers and Phillies were both 2.5 games out. Hazle was 1 for 4 with an RBI in the game (on July 31) which the Braves won 4-2. So by the time Hazle started a game, the Braves had already had a swing of 3 games relative to the Cards. That was in just 18 days without Bruton.
Hazle next played on Aug. 4. At the close of play on the Aug. 3, the Cards were now 1 game ahead of the Braves. Hazle went 2 for 3 and the Braves won 9-7.
But Hazle would play in 20 more games that August and his average was .493 for the month (in 67 ABs). His OBP was .564 and his SLG was .806. He played almost exclusively against righties, with only 3 of his 134 ABs that year coming against lefties.
He batted "only" .317 in Sept but by the time that month started, the Braves now had a 7 game lead, with the Dodgers in being in 2nd. So his incredible August shot them to a very comfortable lead by time Sept began
The Braves finished 8 games ahead of the 2nd place Cards. The Braves' lead did get as low as 2.5 games on Sept 15 but by the close of play on Sept 21 it was back up to 5 games and in the month their lead was less than 4 games for a total of only 3 days.
Hazle happened to also hit well with runners on base that year (.466 in 58 ABs), with runners in scoring position (.552 in 29 ABs) and .471 in Close & Late situations (17 ABs).
If I used the Baseball Reference Play Index correctly, here is what he batted in Aug in the following situations
RISP .611 (18 ABs, SLG was 1.056)
ROB .600 (30 ABs, SLG was 1.000)
Close & Late .600 (5 ABs)
For Close & Late I used when the Braves were tied, ahead by 1 or behind by 1 from the 7th inning on. For someone who still had what today would be considered rookie status to have such a big month when Braves pulled away with a key starter hurt is mind boggling.