Daniels' spokesman Jane Jankowski said the governor neither encouraged nor discouraged Mourdock from launching a Senate run.
"He told Mr. Mourdock it was his decision and he had the right to make it," Jankowski said, in response to Mourdock's comments.
Mourdock said he plans to brand Lugar as President Obama's favorite Republican in the campaign. He's already received support from a majority of the Republican county chairmen and members of the GOP executive committee members in the state.
Mourdock said he does not expect to receive endorsements from any of the state's Congressional Republicans, but he argued that the silence coming from Capitol Hill does not bode well for Lugar. Sen. Dan Coats (R) and Rep. Mike Pence (R) have both opted to remain neutral in the race.
"Why aren't they endorsing a 35-year incumbent?" Mourdock asked. "The fact that MSNBC has labeled Senator Lugar President Obama's favorite Republican says to me it's not just the casual observance of a few people in Indiana. He's been very close to the president, and that's not a good position for a Republican in Indiana right now."
Mourdock also pointed to Lugar's focus on international issues as evidence that he has lost touch with the concerns of Indiana residents. The unemployment rate in Indiana was mired in double-digits for most of last year.
"[Voters are] less concerned about the movement toward democracy in a place like Yemen than they are about the movement of Hoosier jobs to India and China," Mourdock said.
While Mourdock criticizes Lugar for being insufficiently conservative, he said he wasn't worried Indiana could become the latest state where a conservative wins the primary but runs too far to the right to win a general election. He noted that Indiana is a Republican state, and questioned whether Lugar's warm relations with Obama helped the president become the first Democratic presidential candidate to win the Hoosier State since 1964.
And he argued that he is hardly an inexperienced conservative activist. The 59-year-old Mourdock has run for office six times on the Republican ticket, and has close ties to much of the state's Republican establishment. He said he was recruited to run for former Rep. Brad Ellsworth's old House seat last year, but passed on the opportunity.
No Democrats have entered the race yet, but Rep. Joe Donnelly (D) is a possible contender, given that his House seat will likely be altered in the upcoming redistricting. Mourdock said that Donnelly's interest in the race is proof positive that even Democrats believe Lugar is vulnerable in the primary.
-- Julie Sobel contributed to this report.