Michelle A. Smith, a Treasury Department spokesperson, wrote in an e-mail message that Summers "has indicated an interest in thinking about his experiences in the administration, considering current economic issues and contemplating his future."
A university presidency would be a logical step for a Brookings fellow, Nessen said.
"It would not be surprising for someone to go from Brookings to a university presidency," Nessen said.
Smith declined to say whether Summers is still a candidate for the Harvard job.
But think tanks are often a first step for government officials after they leave public service, said Elaine C. Kamarck, a lecturer at the Kennedy School of Government and a former Clinton administration official.
--Staff writer David H. Gellis can be reached at gellis@fas.harvard.edu.