Rob Demovsky says the Packers plan to start Aaron Rodgers in Green Bay's third preseason game and then shut him down until the start of the season. (0:50)

GREEN BAY, Wis. -- Aaron Rodgers still needs some preseason work, according to one of his long-time coaches, and that's why the Packers' quarterback is expected to make his summer debut Friday at the San Francisco 49ers.

Rodgers said that this will be a one-shot deal for the preseason; he's not expecting to play in the finale at Kansas City.

Rodgers hasn't played in either of the first two games, but Packers associate head coach Tom Clements said that even a two-time MVP quarterback, who is entering his 12th NFL season (and ninth as a starter), could use the work.

"The preseason is obviously different than practice," said Clements, who was Rodgers's quarterbacks coach from 2006 to 2011 before being promoted to offensive coordinator in 2012 and then to his current position last year. "Things move fast, faster. Once the season starts, they move even faster. You get to the playoffs, and they move even faster. Regardless I think of how long you've been around, you need a little bit of work before the season starts."

Packers coach Mike McCarthy wouldn't commit to anything specific for Rodgers.

"The goal is to obviously play Aaron and play our guys," McCarthy said before Tuesday's practice. "But we'll evaluate today's practice and we'll have that meeting tomorrow."

Packers QB Aaron Rodgers hasn't played yet this preseason but he is expected to start vs. the 49ers on Friday. Jeff Hanisch/USA TODAY Sports

Rodgers said he will do anything McCarthy "wants me to do" in Friday's game.

"We haven't talked about play time yet. I'll find out probably shortly before you guys find out. I think I'm going to play. I'm not sure how long he wants me to play. But it'll be good to get out there and get some work with the guys," he said.

Rodgers, 32, took his usual workload early in training camp but then shifted into a different role in advance of the preseason games. He worked more with the scout team offense, while McCarthy prepared backup quarterback Brett Hundley along with rookies Joe Callahan and Marquise Williams to play.

This week, however, Rodgers was back at the helm with the No. 1 offense, which was the first sign he would play against the 49ers.

"Aaron has been very sharp in practice," Clements said. "We haven't discussed what the exact play time will be, but I'm sure he'll play. I anticipate that he'll be sharp. But really you have to be moving around quicker than you do in practice. It tests your stamina a little bit more; you have to get used to that. You have to get used to -- get reacclimated to the speed of the game because as I said it's different than practice. But at this point it's like riding a bike: You've been there, you've done it, you know how to do it and you just have to go in and practice it a little bit and get ready."

It's not necessary for Rodgers as much as it is for the offense as a whole.

"What you're looking for any time you put him out there is just going to be how the other guys react, the new guys, [fullback Aaron] Ripkowski getting to play with him for the first time and extensively," said Packers quarterbacks coach Alex Van Pelt. "Jared Cook, Ty Montgomery coming back now after missing time. Just for those guys to feel the stress of what it's like to play and the expectations that come from the offense with him. That's the kind of things he may not get stuff out of it but other guys definitely will feel it."