AKIPRESS.COM - Muhammad Ali was back in the hospital Thursday for follow-up care related to a severe urinary tract infection, his second stint in the hospital in the last four weeks.

The three-time former heavyweight champion was admitted to an undisclosed hospital earlier this week, Ali family spokesman Bob Gunnell said Thursday. Ali is in stable condition, reports AP.

Ali was hospitalized on Dec. 20 with what was initially believed to be a mild case of pneumonia. Doctors later determined Ali was suffering from a urinary tract infection, not pneumonia, Gunnell said.

Ali turns 73 on Saturday and hopes to spend it at one of his homes with family, Gunnell said. Ali and his wife, Lonnie, have homes in Paradise Valley, Arizona; Berrien Springs, Michigan; and in Louisville.

Gunnell said he expects Ali's birthday to include watching the Louisville-Duke men's college basketball game. Ali is a Louisville native, and the Muhammad Ali Center — which showcases Ali's humanitarian causes and boxing career — is a popular attraction in Kentucky's largest city.

Ali's public appearances have diminished in recent years as he wages his long-running fight against Parkinson's disease, but he still enjoys getting out and watching sports and visiting friends.

Ali retired from boxing in 1981 and devoted himself to social causes. He has traveled the world on humanitarian missions, mingling with the masses and rubbing elbows with world leaders.