Rice was unpicked in the 2014 Draft, but Harbaugh said that the wide receiver has a strong understanding of the Ravens' plays and has excellent athleticism for his size.
"Yeah, I'll tell you, Jerry Rice Jr has done a nice job," Harbaugh told the Ravens' official website. "First of all, he is a really good athlete. He doesn't have his dad's size, but he's sure got his athleticism. When you watch him run, he runs in a real similar way.
"And the other thing is he's got that West Coast offense down. He has probably had that playbook since he was in the cradle. He knows all the rules on the crossing routes and what to do, very good hands, very smooth athlete. He did a real nice job."
Rice has previously said that his aim is just to make the 90-man training camp roster.