The transfer from Norwich University in Vermont thought he would be a valuable practice player, allowing the Golden Bears to better prepare for other big men.
Instead, the 6-foot-10 junior walk-on finds himself as one of the few remaining bench options left for Cal because of transfers and ineligibility.
Last Thursday, just one day after sophomore forward Richard Solomon was declared out for the rest of the season because of academics, Thurman scored a game-high 16 points in a 69-66 win at Washington.
"I'm pretty sure if we didn't have Robert's points and him out there helping us rebound, we probably wouldn't have pulled off that win," guard Allen Crabbe said. "He definitely came in and is taking advantage of his opportunity."
Cal (16-5, 6-2 Pac-12) will need that kind of unexpected, but welcome, production from Thurman and junior guard Brandon Smith, the only reserves to see more than 10 minutes of action in each of the last three games.
"Probably throughout the course of the remaining season I'm going to have to get more comfortable with some other players and try to get them in," Cal head coach Mike Montgomery said. "But if they are going to hurt us or can't maintain a certain level, then I can't do it."
Montgomery said fatigue became an issue in the loss at Washington State, but there isn't much that can be done about it.
"We don't have a lot of depth," he said. "It probably bit us in the behind on Saturday given the minutes we had to play on Thursday. I thought we were tired."
Fortunately, the schedule gave Cal eight days before its rivalry game against Stanford at Haas Pavilion on Sunday (5:30 p.m., Comcast Sportsnet Bay Area).
The Cardinal (15-5, 5-3 Pac-12) has good depth, with eight players averaging more than 14 minutes in conference play. It is especially evident in the frontcourt, where even occasional starter Andrew Zimmerman is playing almost 10 minutes per game.
"They got good players and they got a lot of them," Montgomery said. "They can run a lot of people at you."
For Thurman, it makes his contributions all the more vital.
He served as the primary forward during the team's trip to Europe last August, giving him an opportunity to become comfortable as a go-to option, "the man inside" as Montgomery put it.
"He was scoring a lot of buckets and he got comfortable with that," Montgomery said.
Thurman capitalized with a lot of easy looks against Washington, but Washington State paid him more attention defensively, something unlikely to change going forward.
"I'm sure I'm already on people's scouting reports," Thurman said. "Just ‘Don't leave open for wide-open dunks.'"
Anything he can provide might be the difference in winning a conference championship, an unlikely result as Thurman is well aware.
"Just got a strange turn of events throughout my career here."