Albert Pujols is going into his farewell season as a single man -- the MLB legend just announced his divorce from his wife of more than 2 decades.

"I've been asked a lot of questions over the past few days regarding what's been going on at home and sadly, after 22 years of marriage, I have made the decision to file for divorce from my wife, Deidre," Pujols said in a statement.

Pujols acknowledges the timing of the news -- considering his wife had brain surgery to have a tumor removed last week -- is not ideal ... but the split wasn't "something that just happened overnight."

"As a devout Christian, this is an outcome that I never wanted to see happen. For many long days and nights, I prayed, asking the Lord for His guidance."

Pujols -- who married Deidre in 2000 -- did not go into detail about the breakup.

"I am thankful for the five beautiful children that we brought into this world and remain committed to raising them in a loving and safe environment."

Pujols -- who spent the majority of his career with the Cardinals and Angels -- is a 2-time World Series champ, 3-time National League MVP and 10-time All-Star. He's hit 679 home runs in his career ... which is fifth all-time.