NORFOLK, Va. — Republican presidential candidate Mitt Romney has decided on a running mate and will announce his decision Saturday morning in Norfolk, Va., ending a monthslong search and kicking off a four-state bus tour to introduce the GOP ticket to the nation.

Romney advisers wouldn’t disclose the name.

In a statement issued Friday night, the campaign would only go so far as to say that the running mate would be revealed at 9 a.m. at the start of a four-state bus tour at the Nauticus Museum. Berthed at the museum is the USS Wisconsin — which Republicans said likely offered a hint about Romney’s choice.

That and other signs seemed to point to Wisconsin Rep. Paul Ryan, the seven-term Wisconsin congressman whose nomination could help assuage the conservative base of the party that has been reluctant to fully embrace Romney.

In recent days, conservative pundits have been urging Romney to choose Ryan in large part because of his authorship of a House-backed budget plan that seeks to curb overall entitlement spending and changes Medicaid into a voucher-like system to save costs.

On Thursday, Romney fueled the buzz around Ryan, telling NBC that he wants a vice president with “a vision for the country, that adds something to the political discourse about the direction of the country.”

Several Republicans took that as an indication that Ryan had shot to the top of a short list said to include Ohio Sen. Rob Portman and former Minnesota Gov. Tim Pawlenty. Neither of those Republicans had plans to be in Virginia on Saturday.

Ryan, 42, is viewed by some in the Republican Party as a bridge between the buttoned-up GOP establishment and the riled-up tea party movement that has never warmed to Romney.

As the chairman of the House Budget Committee, Ryan could help Romney make the argument that only the GOP ticket knows how to turn around a nation in the midst of a sluggish economic recovery. As talk about Ryan swirled this week, Democrats have been castigating Romney for embracing the Ryan-sponsored budget proposal that critics say is painful to the poor and elderly. It was a sign of the line of attack to come if Ryan is on the ticket.

The move also would link Romney directly with House Republicans, including no-compromise tea partyers who have pressed for deep spending cuts. President Barack Obama has been casting House Republicans as an impediment to progress in the often-gridlocked Washington.

At the same time, Ryan on the ticket could help Romney become more competitive in Wisconsin, a state Obama won handily four years ago but that could be much tighter this November.

Adding fuel to the speculation, Romney’s son Tagg also joined Ryan at a funeral for victims of the Wisconsin Sikh temple shooting on Friday, though the younger Romney said he is planning to campaign in New Hampshire over the weekend and is not attending the bus tour. And a plane was tracked Friday on a flight from Boston to Janesville, Wis., where Ryan lives.

The Wall Street Journal, in an editorial on Thursday, praised Ryan as a strong choice for Romney: “The case for Mr. Ryan is that he best exemplifies the nature and stakes of this election. More than any other politician, the House budget chairman has defined those stakes well as a generational choice about the role of government and whether America will once again become a growth economy or sink into interest-group dominated decline.”

Party officials say Republican National Committee Chairman Reince Priebus has been convinced for days that Romney had settled on Ryan, according to multiple people who spoke with the chairman. Priebus, who, like Ryan, is from Wisconsin, is expected to attend Saturday morning’s announcement.

Pawlenty was maintaining his Saturday schedule campaigning for Romney in New Hampshire, an official close to Pawlenty’s political team said. The person spoke on the condition of anonymity because the person was not authorized to speak ahead of the formal announcement.

Most of Romney’s staff learned of the looming announcement during a 10 p.m. conference call Friday about an hour before the campaign issued a statement. The identity of Romney’s pick was not disclosed during the call.

There were signs of a potential announcement as most of Romney’s senior staff joined him on the flight from Boston, and the campaign added a last-minute rally to their Virginia itinerary on Saturday.