Republican Rep. Bill Cassidy will challenge Democratic Sen. Mary L. Landrieu in Louisiana, in what’s likely to be one of the most competitive races of 2014, CQ Roll Call has confirmed.

The Associated Pres reported Tuesday that Cassidy will officially announce his candidacy in a video to be released on Wednesday.

Cassidy has long been mentioned as a top potential contender to Landrieu, who is seeking a fourth term in a state President Barack Obama lost by 18 points in November. Cassidy had more than $2 million in the bank by the end of 2012, and his campaign announced Monday that he raised $500,000 in the first quarter.

Some Republicans, including Rep. Charles Boustany Jr. and Lt. Gov. Jay Dardenne, have already announced they will not seek the seat. Others, including Rep. John Fleming and former Rep. Jeff Landry, are seen as potential candidates and may still run.

Landrieu has survived tough challenges before, and as a top GOP target, Cassidy’s candidacy ensures she’s in for another tough fight.