Pennsylvania Gov. Tom Corbett (R) gave businessman Steve Welch his backing this week in the crowded GOP primary to take on Sen. Bob Casey (D) this year.

Corbett’s support is intended to put Welch above the fray of GOP contenders as local Republicans attempt to sift through the field of mostly wealthy contenders before the April 24 primary.

“I am proud to announce that Governor Tom Corbett has endorsed me for the United States Senate,” Welch wrote in an email to supporters today. “The Governor understands what it takes to win a statewide election as he has done three times now. He has also proven that not only can we win Pennsylvania, but we can win it big.”

Casey is favored to win re-election this year. Several Republicans are seeking to challenge him — too many candidates, local GOP operatives say, for the party to harness its resources to focus on the Senator. In addition to Welch, businessman Tim Burns, retired coal company owner Tom Smith, attorney Marc Scaringi, and former state Rep. Sam Rohrer are seeking the GOP nod.

Keystone State Republicans are quietly attempting to shrink the field of contenders. PoliticsPA, which first broke the news of Corbett’s endorsement, also recently reported the governor encouraged Burns to run for Congress again instead of for Senate.

But so far, none of them are budging. In fact, candidates continue to up the ante with money from their own pockets. Earlier this month, Smith announced he poured just more than $4 million of his own funds into his campaign in the last quarter of 2011.

Burns and Welch also have the ability to self-fund some of their respective campaigns, but their recent fundraising totals were not yet available. Candidates must file their quarterly fundraising reports by the end of this month.