Summers is "in the process of choosing an agent," Georgetown coach John Thompson III said Monday in a statement issued by the school.
"We wish DaJuan all the best in his future endeavors, wherever they may take him," Thompson said. "He informed me that he is closing the book on his college career and focusing fully on the opportunity to play professionally."
Summers averaged a team-leading 13.6 points for the Hoyas this season, along with 4.1 rebounds.
Georgetown was ranked as high as No. 9 in the AP Top 25 poll after beating Final Four participant Connecticut in January. But the Hoyas dropped 12 of their final 16 games, including a loss to Baylor in the first round of the National Invitation Tournament, to end up 16-15 this season.
The 6-foot-8, 236-pound Summers leaves Georgetown tied for 29th in team history with 1,129 points.
He averaged 11.2 points and 4.4 rebounds in his 101-game college career.