Given the war's hefty price tag and deficit concerns at home, however, Obama is facing increasing pressure from within his own party to make significant changes in the number of U.S. troops on the ground while facing resistance from the Pentagon and some Republicans on making such a move. There are about 100,000 troops on the ground in Afghanistan.
Sen. Carl Levin, D-Mich., head of the Senate Armed Services Committee, has said he wants 15,000 troops out by December. But Sen. John McCain, R-Ariz., a proponent of U.S. engagement, has said the number should be no more than 3,000.
The administration is reportedly mulling pulling 5,000 combat troops in July, and about an additional 5,000 by the end of the year. Sources say that when Obama announces the July withdrawal numbers, he will also announce a timetable for the return home of the 30,000 surge troops he ordered into Afghanistan 18 months ago. Those troops are likely to return by late next year.
Crocker, who has served as ambassador to Lebanon, Kuwait, Syria, Pakistan and Iraq, is expected to be confirmed on a bipartisan basis.
ABC News' Luis Martinez contributed to this report.