Yesterday’s buzz that Jim Hagedorn (R) would join the field of would-be challengers to sophomore Rep. Tim Walz (D-Minn.) proved correct.

Hagedorn released a statement Wednesday morning announcing his campaign — MInnesota Public Radio has the details.

That pushes to three the number of Republican candidates that have joined the 1st district race in the past month.

UPDATE: The Republican party in Minnesota is joining the anti-Walz brigade with a new radio ad, running in the southern Minnesota district today “into next week,” that goes after the Democrat’s support of the health care overhaul.

CQ Politics rates the general election contest Likely Democratic.

To follow all the 2010 Senate races, check out our election map.