Rep. Connie Mack (R-Fla.) has changed his mind and will run for Senate next year, according to a source with knowledge of his plans.

Mack adds new blood to an already pitched Republican primary to face Sen. Bill Nelson (D-Fla.).

Mack earlier this year opted not to run and backed state Senate President Mike Haridopolos (R). But Haridopolos later dropped out of the race, and nobody in the GOP field has asserted himself as the clear frontrunner.

Former state representative Adam Hasner (R) and former senator George LeMieux (R) were both badly outraised in the third quarter, bringing in $535,000 and $400,000, respectively, while Nelson brought in a very strong $2 million.

In Mack, Republicans believe they have a rising star with a golden name. Mack’s father, of the same name, was a two-term senator from Florida in his own right.