Heyward's second MLB season commenced in a fashion that reprised the high expectations from his rookie season, but injuries ultimately factored into a lengthy and dramatic slump.
In the spring, he was diagnosed with a degenerative condition in his lower back.
Like his first MLB at-bat, he began with a home run in his first at-bat of the season on March 31, off Nationals pitcher Liván Hernández.
He became just the second player, after Kazuo Matsui, to homer in his first major league at-bat on opening day, and do the same the following year.
Since being drafted in 2007, it was also the third time Heyward homered in his first game of the season.

In a back-and-forth game with the Giants on April 24, he hit a go-ahead home run off relief pitcher Jeremy Affeldt in a 9–6, ten-inning victory.
In the final eight games of the month, he hit .400 with three home runs and a .714 slugging percentage.
 For the month of April, Heyward hit seven HR with an .879 OPS.
Having previously been represented by Victor Menocal from Career Sports Entertainment (CSE) until Menocal resigned from CSE, news emerged on May 6 that Heyward switched his agent to Casey Close.

From the beginning of spring training, Heyward endured lingering shoulder soreness.
After collecting just four hits in 41 at bats in May, the Braves performed a magnetic resonance imaging (MRI) scan on May 12 which revealed an inflamed rotator cuff but no structural damage.
He rested and received a cortisone injection, but aggravated the injury days later during batting practice.
The Braves placed him on the disabled list (DL) on May 22.
Public criticism from teammate Chipper Jones for not playing through his injuries followed the next month; said Jones, "I think where Jason might have erred was the comment that he made, 'I'm not coming back until it doesn't hurt anymore.' ...
What Jason needs to realize is that Jason at 80 percent is a force, and Jason at 80 percent is better than a lot of people in this league."
Jones later explained that he reassured Heyward in a phone call that he did not intend to misrepresent Heyward's efforts to rehabilitate.

Heyward returned from the DL with increased difficulty to drive the ball while batting.
A sixth-inning home run against the Baltimore Orioles on July 1 was Heyward's first since April 29 against the St. Louis Cardinals, a span of 104 at-bats.
 However, he hit just four home runs from the end of April through August 11.
 Further, his walk rate declined from 14.6 percent the year before to 10.7 percent.
His line drive rate in that time dropped from 17.8 to 13 percent and one-quarter of his balls hit in the air were infield pop-ups, compared with eight percent the year before.
During a game against the Chicago Cubs on August 23, he hit his first career grand slam.

Through the end of August, the Braves were the NL wild card leader.
However, the Cardinals overcame a ​10 ¹⁄₂-game deficit for the wild card position by winning 20 of their final 28 to eliminate the Braves from the playoffs on the final day, consummating one of the epic late-season collapses in MLB history.
After battling a shoulder injury from the beginning of the season, Heyward's overall performance dropped off from his rookie season.
His batting average dropped 50 points to .227; his other contributions, also in decline, included 14 HR, 42 RBI, 18 doubles, and nine stolen bases in 128 games.
He batted .240 against right-handed pitchers, compared with .192 against left-handers.
Heyward's second MLB season commenced in a fashion that reprised the high expectations from his rookie season, but injuries ultimately factored into a lengthy and dramatic slump. In the spring, he was diagnosed with a degenerative condition in his lower back. Like his first MLB at-bat, he began with a home run in his first at-bat of the season on March 31, off Nationals pitcher Liván Hernández. He became just the second player, after Kazuo Matsui, to homer in his first major league at-bat on opening day, and do the same the following year. Since being drafted in 2007, it was also the third time Heyward homered in his first game of the season.
In a back-and-forth game with the Giants on April 24, he hit a go-ahead home run off relief pitcher Jeremy Affeldt in a 9–6, ten-inning victory. In the final eight games of the month, he hit .400 with three home runs and a .714 slugging percentage.  For the month of April, Heyward hit seven HR with an .879 OPS. Having previously been represented by Victor Menocal from Career Sports Entertainment (CSE) until Menocal resigned from CSE, news emerged on May 6 that Heyward switched his agent to Casey Close.
From the beginning of spring training, Heyward endured lingering shoulder soreness. After collecting just four hits in 41 at bats in May, the Braves performed a magnetic resonance imaging (MRI) scan on May 12 which revealed an inflamed rotator cuff but no structural damage. He rested and received a cortisone injection, but aggravated the injury days later during batting practice. The Braves placed him on the disabled list (DL) on May 22. Public criticism from teammate Chipper Jones for not playing through his injuries followed the next month; said Jones, "I think where Jason might have erred was the comment that he made, 'I'm not coming back until it doesn't hurt anymore.' ... What Jason needs to realize is that Jason at 80 percent is a force, and Jason at 80 percent is better than a lot of people in this league." Jones later explained that he reassured Heyward in a phone call that he did not intend to misrepresent Heyward's efforts to rehabilitate.
Heyward returned from the DL with increased difficulty to drive the ball while batting. A sixth-inning home run against the Baltimore Orioles on July 1 was Heyward's first since April 29 against the St. Louis Cardinals, a span of 104 at-bats.  However, he hit just four home runs from the end of April through August 11.  Further, his walk rate declined from 14.6 percent the year before to 10.7 percent. His line drive rate in that time dropped from 17.8 to 13 percent and one-quarter of his balls hit in the air were infield pop-ups, compared with eight percent the year before. During a game against the Chicago Cubs on August 23, he hit his first career grand slam.
Through the end of August, the Braves were the NL wild card leader. However, the Cardinals overcame a ​10 ¹⁄₂-game deficit for the wild card position by winning 20 of their final 28 to eliminate the Braves from the playoffs on the final day, consummating one of the epic late-season collapses in MLB history. After battling a shoulder injury from the beginning of the season, Heyward's overall performance dropped off from his rookie season. His batting average dropped 50 points to .227; his other contributions, also in decline, included 14 HR, 42 RBI, 18 doubles, and nine stolen bases in 128 games. He batted .240 against right-handed pitchers, compared with .192 against left-handers.
Jason Heyward