CHICAGO -- Tony La Russa is stepping down as Chicago White Sox manager because of health concerns that kept him out of the dugout for the final five weeks of the season, he announced in a statement released Monday.

La Russa, who will turn 78 on Tuesday, hasn't managed a game since abruptly leaving Guaranteed Rate Field on Aug. 30 after doctors told him he needed to undergo further testing related to a heart issue.

According to La Russa on Monday, there was an issue with the pacemaker he had implanted in February that forced him to step away from the team. During his absence, a second issue was diagnosed, forcing him to take an indefinite leave.

He was under contract through the 2023 season.

"At no time this season did either issue negatively affect my responsibilities as White Sox manager," La Russa said in the statement. "However, it has become obvious that the length of the treatment and recovery process for this second health issue makes it impossible for me to be the White Sox manager in 2023. The timing of this announcement now enables the front office to include filling the manager position with their other off-season priorities."

La Russa also noted that his "overall prognosis is good, and I want to thank everyone who has reached out to me with well wishes related to my health."

In La Russa's absence, the underachieving White Sox did get an initial boost from acting manager Miguel Cairo, but that was short-lived, as the team was swept at home by the Cleveland Guardians in a key September series. It went on to lose eight in a row and is now hoping to at least finish at .500 or above for the third consecutive season.

"Our team's record this season is the final reality," La Russa said in the statement. "It is an unacceptable disappointment. There were some pluses, but too many minuses. In the Major Leagues, you either do or you don't. Explanations come across as excuses. Respect and trust demand accountability, and during my managerial career, I understood that the ultimate responsibility for each minus belongs to the manager.

"I was hired to provide positive, difference-making leadership and support. Our record is proof. I did not do my job."

La Russa's second stint with the team, after managing the White Sox in the early 1980s, drew headlines for his unorthodox moves, but the team won the American League Central Division by 13 games in his first season.

This year has been anything but smooth. The White Sox have hovered around the .500 mark all year despite being preseason favorites to win the division again. La Russa intentionally walked two batters who had two strikes on them, further garnering headlines and controversy.

La Russa expressed disappointment in not being able to see things through with the White Sox but noted that the "future for this team remains bright."

"I still appreciate the chance to come back home to the White Sox and leave today with many more good memories than disappointments," he said. "As I have said many times during my career, no manager has ever had more good fortune than I have."