He got out of the ICU on Monday.
In a tweet posted on Tuesday, Manuel gave a shout-out to those who are keeping him in their thoughts.
"I want to thank all the people who are pulling for me. I am touched that you are showing me love," the tweet reads.
The 79-year-old Manuel also thanked the Lakeland, Florida hospital where he is being treated, saying they "kept me in the game."
Manuel led the Phillies to a World Series victory in 2008.
He won more games (780) than any manager in team history and has 1,000 career wins, including three seasons with Cleveland.