A businessman regarded as a prime contender for the 2010 Republican nomination for Minnesota governor has decided against running for the open office.

Brian Sullivan said Friday that he couldn’t be an effective campaigner while tending to a fast-growing medical services company.

His move further jumbles the 2010 nomination battle, set off by Gov. Tim Pawlenty’s decision not to seek a third term.

Sullivan, a Republican National Committee member, lost a spirited endorsement contest to Pawlenty in 2002. His personal wealth gave him an advantage over other Republicans considering bids this time.

Sullivan isn’t endorsing another Republican at this point. Several current and former legislators are weighing campaigns.