After a couple weeks of building staff, hiring consultants and being given office space, Rep. Nikki Haley will announce for governor this week, sources tell WR. Some are saying the announcement could come as early as Thursday.

In the past several days, she has hired Maryland-based consultant Jon Lerner, who does a significant amount of work for the national Club for Growth and ran Gov. Mark Sanford’s 2006 campaign. She also hired Tim Pearson, former rapid response man for Rudy Giuliani’s presidential campaign, to do her communications work, along with bringing in other lower-level staffers.

With U.S. Rep. Gresham Barrett and Sen. Larry Grooms already in the race, and Atty. Gen. Henry McMaster and Lt. Gov. Andre Bauer expected to jump in, Haley will be the fifth candidate in the Republican primary, having to battle the big three for money and grassroots support. She will also have to compete with Grooms for the Sanford-friendly types, both in dollars and on the ground. However, her tie-in with Lerner could signal that Sanford allies are already organized behind her bid.

UPDATE: Word into the WR newsroom is that Justin Evans, formerly a research associate with the S.C. Policy Council, has already left the SCPC to work for the Haley campaign.

Sources close to WR are saying that Rep. Nikki Haley’s gubernatorial bid is continuing down the tracks, with the hiring of Tim Pearson, who will be heading up communications for the campaign.

Recently, Pearson was the rapid response director for former N.Y. Mayor Rudy Giuliani’s presidential campaign. More recently, he was the deputy communications director at Freedom’s Watch, a now-defunct organization run by former staffers for former President George W. Bush.

As Haley’s campaign moves on creating a full staff, it is only a matter of time until a candidacy announcement, so the effort can make sure the Big 3 don’t lock up all the big-money donors.