Chargers rookie running back Justin Jackson will make his NFL debut this Thursday in the team's preseason finale against the San Francisco 49ers.

After missing the bulk of training camp with a hamstring injury, Head Coach Anthony Lynn said after Tuesday's practice that Jackson is moving well and has fresh legs. Jackson, who was the definition of durable in college, hasn't seen game action since the East-West Shrine Game last January.

"I feel like I have a lot of energy – a lot of want-to, a lot of passion," Jackson said. "I'm just ready to let it loose and just go out there and have fun."

Jackson left Northwestern as the school's all-time leader in rushing yards (5,440) and touchdowns (41). He said he hadn't missed a game his entire career, which has made the last month uncharted waters.

To make up for not practicing, Jackson said he watched film and took as many mental reps as possible. He explained that staying sharp mentally should make his transition back to the field seamless.

"I feel really good, like I haven't missed a beat," he said. "Because even though physically I wasn't there doing it, I'm there mentally and so, I've already imagined myself doing this, doing that. So, I think it's been a lot easier for me to come back and not really miss a step."

Lynn said they don't want to run Jackson too much on Thursday, but he'll still get plenty of snaps in Santa Clara.

"He hasn't been in action in a long time, but he's going to play a lot," Lynn said.