But the 23-year-old, who was an afterthought in the August trade that sent Carlos Delfino and Roko Ukic to the Milwaukee Bucks for Amir Johnson and himself, showed he was more than capable.
"Anybody who is sitting on the bench, it's not a good mental thought," Weems said. "You kind of get down because you know you can play with these guys.
"I'm always ready. Whatever it takes for me to get on the court, I am going to do it."
Pro athletes always prepare as though they will be in the lineup, but staying sharp mentally is a different task.
Another Raptors backup, Marcus Banks, said it's one of the more difficult aspects of the job, but simply has to be done.
It's not easy to make an adjustment from doing sprints in an empty arena to being thrown into a game before 17,000 fans. What makes Weems attractive for Triano is he's one of the Raptors' more athletic players.
And with a group as defensively poor as the Raptors, they will take what help they can get.
"Sonny is one of the guys who can keep a lot of people in front of him," Triano said. "We just tried to keep him on the floor as much as we could.
"He has brought us good energy, and he will definitely earn more minutes."
Weems got some off-court guidance from another Raptors newcomer, guard Jarrett Jack.
Signed as a free agent in July, Jack has been easing into a leadership role gradually and has filled in well for Jose Calderon, whose hip injury stopped him from making the trip.
"One thing I have been telling Sonny is to keep his head up," Jack said. "I know he was anxious.
"I'm a vocal person and I will try to help guys out when I see something. It's my personality, more than anything."