Veteran first baseman Adam LaRoche plans to retire from baseball for undisclosed personal reasons and will likely make a more formal announcement before the weekend. He acknowledged his decision was not final, but said he does not think he will change his mind.

The 36-year-old was headed into the final season of a two-year contract worth $25 million in total. LaRoche has been dealing with back spasms during spring training and sat out Monday when Chicago White Sox manager Robin Ventura expected him to play.

When LaRoche told his Chicago White Sox teammates Tuesday morning he intended to retire, they asked him to reconsider. He said he agreed to oblige their request and promised a final decision in "a day or two," and appears likely to sit out in the meantime.

"I'm confident I am stepping away from baseball," LaRoche said. "My teammates have asked me for an hour [to reconsider]. I've tried to convince them I am convinced, but I will do them that, and give it a day or two, and then come back in and finish the story."

LaRoche did not go into detail about the reason for his sudden retirement, but said it was personal.

"I want to sleep on it again," he said. "I didn't come in yesterday because I wanted to make sure it was the right move and make an emotional decision. I'm confident it is. Out of my respect for these guys and [general manager] Rick [Hahn] they asked me to give it a day or two to confirm."

Ventura said Monday LaRoche needed an extra day before returning to the lineup, but stated it was not because of an injury setback. The White Sox played on the road Monday and returned to their home spring training field Tuesday. Headed into this season as the White Sox primary designated hitter, LaRoche left Saturday's game with spasms in his lower back and has not played since.

LaRoche stands to miss out on the rest of his contract if he retires, which is about $13 million.

Over 12 seasons playing for the Braves, Pirates, Red Sox, Diamondbacks, Nationals and now White Sox, LaRoche hit 255 home runs and registered a .462 slugging percentage. His best season was 2012 when he hit 33 home runs and drove in 100 runs, finishing sixth in MVP voting and taking home a Gold Glove and Silver Slugger.