"As you know, it's been a long road," Lattimore said.
Lattimore said he reported to training camp at 225 pounds but is down to 220 and believes he's quicker, the report said. He's eager to test himself at full-contact practices.
"I want to put together consistently good days of practice so they trust me to go out there and play," he said. "That's the biggest thing."
The 49ers must decide whether to activate Lattimore within three weeks of his first practice.
Gee had been a starter with Cleveland before losing substantial playing time last year. He has struggled throughout his career to make an offensive impact.