Sheridan tells the Janesville Gazette in a story published Friday that he is mulling a run for the seat being vacated by retiring Democratic Sen. Tim Cullen.
Sheridan lost his Assembly seat in 2010 after he disclosed he was dating a lobbyist for the payday loan industry around the time he softened his stance on regulating that industry.
Sheridan has lobbied for the AFL-CIO since 2012. He tells the newspaper that he is considering a run after Democratic state Rep. Andy Jorgensen decided to seek re-election to the Assembly rather than vie for the Senate seat.
Democratic Rep. Janis Ringhand, of Evansville, has announced she is running for the seat.