[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2010/images/01/23/art.hayworth.gi.jpg caption="Hayworth says he will challenge McCain."](CNN) - Former Rep. J.D. Hayworth of Arizona says he's planning to challenge fellow Republican John McCain for his senate seat.
The former six-term congressman stepped down Friday as host of his conservative talk radio program on a radio station in Phoenix.
"We will formally announce at a later time, but we're moving forward to challenge John McCain," Hayworth told the Associated Press. "I think we all respect John. I think his place in history is secure. But after close to a quarter-century in Washington, it's time for him to come home."
Shiree Verdone, McCain's campaign manager, said in a statement, "Senator McCain has always taken every challenge seriously, and is confident with the help and support from the people of Arizona that he will be re-elected to the United States Senate."
Hayworth would not have been able to continue hosting a radio program and also legally run for federal office. Hayworth was ousted from Congress in the 2006 election and has hosted the radio show for the past few years.
"It has been a joy to spend weekday afternoons on KFYI. Now, another chapter begins. The call to public service remains, and again it may very well lead to pursuit of public office," Hayworth said in a statement posted on the radio station's website.
Hayworth told AP that a recent "outpouring of support" from people in Arizona asking him to run changed his mind about challenging McCain, the 2008 GOP presidential nominee and four-term senator who's up for re-election this year.
McCain's already facing a primary challenge from Chris Simcox, a co-founder of the Minuteman movement. Simcox announced his candidacy last April and then resigned from the volunteer organization, which tries to prevent illegal crossings of the U.S. border. McCain's past support of immigration reform legislation in Congress nearly derailed his presidential bid two years ago.
Wednesday McCain's running mate in 2008, former Alaska Governor Sarah Palin, announced she would travel to Arizona to campaign with McCain in March. Palin is very popular with many voters on the right, and her teaming up with McCain could help him with some Republican voters who question his commitment to conservative values and goals.
- CNN's Paul Steinhauser and David DeSola contributed to this report.