Senate President Emil Jones is expected to announce his retirement plans today, stripping Gov. Blagojevich of his most vocal and reliable ally as the governor contemplates a third term.

The South Side Democrat, who has been in the Legislature since 1973 and led the Senate since 2003, told several members of his leadership team of his plans over the weekend.

“I believe Emil is coming to the end of his time. He’s tired,” said one high-ranking Jones ally, who asked not to be identified but confirmed an announcement would be made today.