Trump will conduct a series of radio interviews in the state this week in support of Romney’s candidacy, reports ABC News.

Trump, who flirted with his own presidential run last summer after polls showed him potentially leading the GOP field, endorsed Romney earlier this month but has not appeared on the campaign trail with him.

Romney, who has been the presumptive GOP fron-runner, was expected to win easily in Michigan, but Rick Santorum now leads in the polls, both in the state and nationally.

A Public Policy Polling survey released Monday, however, shows that Romney has whittled Santorum’s lead down to four points up from a high of 15 points in a survey from last week. 

Both campaigns have devoted significant resources to winning the state and have deployed high-level surrogates to make their case. Romney last week secured the endorsement of Michigan Gov. Rick Snyder (R).

Trump, whose reality show “Celebrity Apprentice” debuted for a new season Sunday night on NBC, has had tough words in the past for Santorum.

In a YouTube video released earlier this month, Trump blasted Santorum after the former Pennsylvania senator scored an upset trifecta of victories in GOP nominating contests in Missouri, Minnesota and Colorado. 

“What someone has to explain to me is, how can somebody who is a sitting senator run for the Senate as an incumbent and lose by 19 points to somebody else, and then say, 'Well, gee, I just lost in Pennsylvania for the Senate by 19 points, now I'm going to run for president'? Explain that to me,” Trump said in the video. 

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