Republican candidate for governor Marty Seifert said Wednesday that he's confident of winning the GOP's endorsement in 10 days, but he's not closing the door on running in the August primary without it.

Seifert briefed reporters on his strategy for the convention and beyond in a morning conference call. It's an eventful day in the GOP race to take on Gov. Mark Dayton in November: another candidate, Hennepin County Commissioner Jeff Johnson, is set to announce his lieutenant governor running mate at a Capitol news conference.

Seifert, Johnson and state Sen. Dave Thompson are expected to vie most seriously for the GOP's endorsement at the state party convention in Rochester on May 31. The other two leading candidates, state Rep. Kurt Zellers and businessman Scott Honour, have already announced plans to advance to the August 12 primary.

Seifert, a former House Republican leader who lost the GOP endorsement for governor in 2010, said he's "open-minded" about the possibility of honoring the endorsement but is unlikely to decide until next week when the convention's nominations committee meets.

Seifert, from Marshall, and Thompson, from Lakeville, have already named their running mates. Both are female state lawmakers: state Rep. Pam Myhra of Burnsville is running with Seifert, while state Sen. Michelle Benson of Ham Lake is on Thompson's ticket. Zellers and Honour have yet to name their picks.