Washington (CNN) - One day after Colorado Gov. Bill Ritter announced he would retire at the end of this year, Interior Secretary Ken Salazar announced he would not run for governor.
Instead, Salazar is endorsing Denver Mayor John Hickenlooper in this year's battle to succeed Ritter, a fellow Democrat.
"Colorado needs a strong, experienced leader with optimism and new ideas for carrying our state forward. That is why I am endorsing John Hickenlooper for Governor of Colorado. John Hickenlooper is a uniter," said Salazar in a statement released Thursday afternoon. "If he decides to run, he will make an excellent Governor for the State of Colorado."
Salazar served as Colorado attorney general before winning election to the U.S. Senate in 2004. He left his Senate seat early last year to join the Obama administration. Hickenlooper is the popular two-term mayor of Denver.
Salazar's move may prevent another Democrat, former Colorado House Speaker Andrew Romanoff, from jumping into the governor's race. Instead Romanoff may remain in his primary battle against Sen. Michael Bennet, whom Ritter named to fill Salazar's Senate seat.
Former Rep. Scott McInnis is the likely Republican gubernatorial nominee.
-CNN's Paul Steinhauser, Ed Henry, Jessica Yellin and Mark Preston contributed to this story