Rodriguez, a Democrat, confirmed today that he has appointed a campaign treasurer and filed the necessary campaign paperwork with the Texas Ethics Commission.
He stopped short of confirming that he will run, saying, "I don't want to make an annoucment today. I want to reserve it for tomorrow."
Rodriguez, who has been county attorney since 1993, is a close friend of Shapleigh, and some consider him a favorite in the Texas Senate race because he has repeatedly been elected countywide.
State Rep. Norma Chavez said she will decide before Thanksgiving whether to make a go at the Senate seat, and former Tigua Gov. Albert Alvidrez has said he is also considering a campaign. Both are Democrats.