Returning from an underwhelming display at the Las Vegas Summer League, Robert Upshaw felt that there was more in him than the 1.4 points and 2.2 rebounds he averaged.

The 21-year-old rookie had not yet signed a contract with the Lakers, essentially putting his NBA future in the dark. Taking control of his side of the situation, Upshaw went to work returning to the physicality that contributed 10.9 points, 8.2 rebounds and 4.5 blocks at Washington last year.

“In Summer League I didn’t feel like myself, and I just didn’t feel as fluid as I usually feel,” Upshaw said. “When I got back to San Diego where I was training, I put an emphasis on being faster, quicker and slimmer.”

Upshaw dropped 20 pounds between Summer League and his signing with the Lakers, reshaping his body beginning with 7 a.m. cardio.

“I would run for an hour and then I would have a basketball workout and then a strength-and-conditioning workout,” he said. “And then I would get shots up at night. I stayed consistent with that for a month and a half, every day, six days a week.”

In addition to not physically feeling like the imposing shot blocker he had been in college, Upshaw also felt motivated by the questioning of his character. After being dismissed from the Fresno State program in 2013, he was asked to leave again by UW last year. Both were due to disciplinary reasons.

He now feels the need to prove that he’s moved beyond his collegiate issues.

“The real reason I (lost weight) was because I felt like I had something to prove,” Upshaw said. “There’s been a lot of talk about the person I used to be and the person that I am. I just want to show everybody that I know who I am and who I can be as a person in this community and with this basketball team.

“I know what person I am. I just know I made a lot of bad decisions twice. When people see that, I feel they say this guy that can’t be anything and won’t be anything. I know that I have a second calling, and it’s going to be a blessing to really do this.”

Upshaw jokes that his new physique is “to look good for the ladies,” but he also recognizes the seriousness of his situation. Fighting for a regular-season roster spot as an undrafted free agent is a tall task even for a seven-footer.

“Nothing’s guaranteed for me,” Upshaw said. “What I really want to do is go out there and show (General Manager) Mitch (Kupchak), the front office, Coach (Byron) Scott and — most of all — my teammates that I can really play at this level and do something to help this franchise.”