Paul, the son of Rep. Ron Paul (R-Texas), is running to the right of Secretary of State Trey Grayson in the GOP primary. Paul’s online grass-roots fundraising has proved to be surprisingly strong, but Grayson remains the choice of most establishment Republicans. Grayson is headed to Washington later this month for a fundraiser at National Republican Senatorial Committee headquarters that will feature nearly two dozen GOP Senators.

With that kind of fundraising power at Grayson’s disposal, the deep pockets of the Club for Growth’s political action committee could be very important in the primary.

But club Executive Director David Keating said Monday that his group is vetting both GOP candidates in the Kentucky Senate race.

“After months of runaway federal spending and record deficits, our members are especially motivated to support high-profile, pro-growth candidates for Congress,” Keating said. “It’s possible that will include Trey Grayson or Rand Paul. There’s not a set timeline for endorsement, but we look forward to meeting with both candidates soon and completing our research on their records, as well as our assessment of the competitiveness of this race, before making any decisions.”

While he’s in town, Rand Paul will be attending a fundraiser hosted by a libertarian women’s group and meeting with several conservative political action committees.

“We ... have good friends in D.C. that are similarly not pleased with the efforts of some to put a middle-of-the-road Republican in the U.S. Senate to represent Kentucky,” Paul campaign manager David Adams said Monday. “I’m encouraged by the response we’re getting as a blow-back against the NRSC fundraising. We think that was a tactical error” on the part of the NRSC to host a fundraiser for Grayson.