House Majority Leader Eric Cantor (R-Va.) endorsed Rep. Adam Kinzinger (R-Ill.) over Rep. Don Manzullo (R-Ill.) Thursday, the latest sign of establishment GOP support for the freshman congressman.

Rep. John Shimkus (R-Ill.) also endorsed Kinzinger. In a joint statement, the two took a shot at Manzullo.

"We work on a regular basis with both Adam Kinzinger and his opponent. We join our colleague Congressman Aaron Schock of Illinois in the judgment that Adam Kinzinger is the right choice to keep advancing our conservative movement," they said in the statement. "Adam Kinzinger is hands down the candidate the conservative cause needs to win the primary for Congress on March 20th and he has our enthusiastic endorsement for a second term in Congress."

Kinzinger has quickly become a favorite of House Republican leaders, and House Speaker John Boehner (R-Ohio) has also donated to his campaign. But while he enjoyed Tea Party support in his 2010 win, some have been unhappy with his relatively centrist voting record. The Illinois Tea Party, a confederation of local Tea Party groups, has endorsed Manzullo.

The district was drawn to pack as many Republicans into it as possible after Kinzinger's district was largely dismantled. The Hill rates this seat as safely Republican.