Another top tier challenger would be Attorney General Greg Abbott. Abbott has made no secret that he is interested in the race. He is considered a rising the star in the Texas GOP and would also be able to raise a lot of money.
A second Railroad Commissioner, Michael Williams (R), is also looking at the race, according to Texas GOP operatives. An African-American Republican, Williams formed an exploratory bid when it looked like Hutchison would vacate her seat to run for governor. His fundraising during that period was poor, however, and state sources put him in the second tier of possible contenders.
Lastly, Dallas Mayor Tom Leppert is also reportedly eyeing the race. Leppert would start with a sizable geographical base but has yet to reach out to many in the party about a Senate run.
A crowded primary field wouldn't allow Hutchison to eke out a narrow win with less than 50 percent of the vote because Texas has a runoff system. If Hutchison fails to get to 50 percent, she would have to face one of her likely more conservative challengers in the runoff, where the challenger would likely benefit from a united anti-Hutchison vote.
If the GOP does nominate a very conservative contender, we could see another instance of a Tea Party backed contender hurting the GOP's chances in the general election. That could open the door to a Democrat, even in Texas.
Already, former Texas Comptroller John Sharp is running for the seat. One of the Democrats' top candidates, 2010 gubernatorial nominee Bill White, told Hotline On Call Monday morning that he won't run for the Senate in 2012.
"I wouldn't rule out public service in the future," White said. But, he added, "I have no plan."
At this point, however, it looks like Hutchison may among the Republicans most vulnerable to a Tea Party challenge in 2012.
This post was updated at 5:04 p.m. with a comment from Hutchison's office.