The 49ers official website reported that Hayne had a "quiet, yet solid" start to training, not having a lot of opportunity to train at running back stuck behind the team's more experienced options in that position.
Hayne said he was pleased to finally be able to run pain-free - in his first of 11 training camp sessions - following his successful surgery.
"It went really well," Hayne told 49ers.com about the surgery.
"The recovery hurt more than anything, not running for three weeks, that's taken it's time.
"I'm still getting my speed and fitness back but I'm at about 80 to 90 percent, which is good."
The former Parramatta Eels star also described how he's working on his running style, hoping to increase his flexibility to allow him to get a lower body position coming into contact.
"It's going to take time," Hayne said.
"I'm sure there are going to be times when I get smashed because I'm running too upright.
"That's part of the learning curve, I don't have fear in that.
"I'd rather get hit hard and learn like that than beat around the bush.
"It's one way you learn from your mistakes."
Hayne also revealed that he's been leaning on team-mate and fellow running back Carlos Hyde for pointers.
Despite being one of rugby league's elite ball runners, the NFL is a totally different ball game with bigger, more powerful defenders equipped with big pads that make breaker through contact far more difficult.
"It's all about technique," Hayne told 49ers.com.
"That's something I asked Carlos about, what technique he uses.
"It's a process and that's one of the final steps in kind of figuring everything I need to do."
While Hayne's best opportunity to play in the NFL will come as a kick return specialist, he needs less practice in that area considering his experience in the NRL and the fact that skill is largely improvisation.
He will spend the upcoming weeks focusing on running the ball out of the backfield and nailing down the fourth running back position in the 49ers roster.
His new NFL team shared this message on Facebook over the weekend:
Hello to everyone back home! Jarryd Hayne checking in from #C4M9.
Posted by San Francisco 49ers on Saturday, 1 August 2015