(CNN) -- Rep. Eric Cantor is expected to relinquish his leadership position as the No. 2 House Republican after losing his Virginia primary in a stunning upset, a senior GOP source tells CNN's Dana Bash.
Cantor is expected to step aside as majority leader on July 31. The decision sets up a leadership scramble among Republicans in the House, which is led by Speaker John Boehner of Ohio.
The heavily favored Cantor lost Tuesday to college professor and political novice Dave Brat, who triumphed in the Richmond-area district with tea party support.
Chaos at Cantor headquarters after loss
Most Republicans viewed Cantor, 51, as the most conservative member in the House leadership and a likely successor to Boehner.
Two sources familiar with the situation have also told Bash it is now less likely Boehner will retire with Cantor out of the picture.
Although Cantor dramatically outspent Brat in Virginia's 7th Congressional District race and most political observers anticipated he would win easily, the cash advantage didn't alter the outcome and he lost convincingly.
Cantor fell by 10 percentage points although turnout was low.