Sen. Sam Brownback (R) filed paperwork on Monday seeking the Republican nomination for the governorship of Kansas in 2010.

Brownback's filing comes after announcing his plan to retire from the Senate in the next election cycle, a move which many believed was a step to organize a run for governor.

Brownback filed documents with the Kansas Secretary of State disclosing that he had appointed a treasurer for a campaign for governor, the Associated Press reported, the first required filing step for state candidates before being able to accept contributions.

The 2010 race represents another pickup opportunities for Republicans in a traditionally-favorable state in which a Democratic governor is term-limited. Gov. Kathleen SebeliusKathleen SebeliusLeaked email: Podesta pushed Tom Steyer for Obama’s Cabinet Romney: Trump victory 'very possible' Fighting for assisted living facilities MORE (D) is barred from seeking reelection.

Republican Secretary of State Ron Thornburgh is thought to be Brownback's major competition for the GOP nomination.