In an article, which appeared in the party mouthpiece Saamna, Thackrey said Sachin should just concentrate on cricket and stay away from politics.
He also warned Sachin that he should not lose the goodwill he has earned in cricket by getting into the political arena.
"When Marathis shed their blood for Mumbai you weren't even born, you have been run out on the Marathi pitch," he added.
Earlier, addressing a press meet on the eve of completing 20 years in international cricket, Sachin had said, "Mumbai belongs to India. I am a Maharashtrian and am extremely proud to proud of that, but I am an Indian first."