He will be again put under the microscope again on Thursday in the final pre-season hit out against the San Diego Chargers at the 49ers' home field, Levi's Stadium.
Tomsula said he knew Hayne had the talent and skill to be a punt returner, with his catching of high balls and open field running developed while playing in the NRL.
What the coach needs to see is more of Hayne's ability in NFL specialist roles as a back-up running back and contributing in other areas of special teams.
"I will say he's busting his tail in those other areas," Tomsula said.
"Guys, we didn't teach Jarryd Hayne how to catch that ball. OK? He came here with that ability.
"We knew that."
Tomsula also didn't rule out recruiting more league and union players.
The coach has more experience in the NFL than most at assessing athletes from non-NFL sports after spending years as a coach in NFL Europe where teams widely recruited.
"I've got a lot of time doing that," Tomsula said.
He said league and union players, with their ability to run in open spaces, are suited to playing as running backs, returners and open-field tackling positions.
In specialist positions like quarterback and offensive lineman, the skill sets don't match up.
"But if you look at the position Jarryd plays, those things translate," Tomsula said.
"Now, playing in tight spaces and pass protections, he is improving, he is improving big time."
-AAP
