The 49ers opened their rookie camp with one spot available on their 90-man roster.Austin Walter, a running back from Rice, earned the spot.The 49ers signed Walter to a three-year contract. Walter announced his signing on social media.I would like to thank the 49ers organization for giving me this opportunity thats not given to most people and I promise to make the most out of it, Walter wrote as the caption under a photo of him signing his contract.