Defense Secretary Robert Gates "still has a lot to do" before retiring from office, the Pentagon's top spokesman said Thursday.

Defense Department press secretary Geoff Morrell said that Gates has a wide window of time next year during which he could retire, noting the indefinite timeline after Gates told Foreign Policy magazine he's likely to retire in 2011.

"This was not an announcement of his retirement," Morrell said of the piece during an appearance on MSNBC.

Gates said he would want to retire before the 2012 presidential election cycle, which would give President Obama plenty of time to find a successor. But a number of unfinished items will carry into next year, including replacing top members of the military, reforming the Pentagon's budgets, and possibly finishing combat operations in Afghanistan.

Morrell noted the numerous items Gates will have to tackle next year, but would not say if the Defense Secretary would, at the least, stay on past July 2011, when coalition forces are set to begin withdrawing from Afghanistan.

"Let's see what happens next year. Clearly there's a lot to do between now and then," Morrell said. "I think he still has a lot to do."

Gen. David Petraeus, the commander of troops in Afghanistan, has argued against a quick withdrawal, possibly protracting U.S. involvement in that country, and Gates's time on the job.

Speculation has begun to murmur since the Foreign Policy piece was reeled on Monday over who might succeed Gates at the Pentagon. Secretary of State Hillary ClintonHillary Diane Rodham ClintonOmar endorses progressive Georgia Democrat running for House seat Bernie Sanders's Super Tuesday problem Democrats worried about Trump's growing strength MORE has been among those whose names have been more frequently bandied about.