HERTFORDSHIRE, England -- As they came off the practice field Thursday morning, 49ers players got an impromptu rugby lesson. Members of the Northampton Saints demonstrated how a scrum works and exchanged a few XXL jerseys with the burly American offensive linemen.
The rugby class did not last long, however. The 49ers need every available second to focus on their day jobs. With Troy Smith introduced as the new starting quarterback this week, the 49ers are scrambling to get their offense ready for the Denver Broncos on Sunday at Wembley Stadium.
Offensive coordinator Mike Johnson acknowledged that the 49ers will have to simplify the playbook in order to keep Smith afloat.
"Yeah, you do," Johnson said. "You have to cut back. You have to scale back."
Smith, the No. 3 quarterback all season, leapfrogged David Carr in the pecking order this week to replace injured starter Alex Smith, who is out two to three weeks because of a separated left shoulder.
Troy Smith, a fourth-year veteran, will be starting for the first time since taking the reins for the Baltimore Ravens' final two games of the 2007 season. When he took snaps with the 49ers' starting unit this week, it marked his first work with the No. 1 unit since signing with the team on Sept. 6.
Left tackle Joe Staley had never even heard his voice in the huddle.
"He did well," Staley said. "He's going in there and doing everything he needs to do. We're just trying to make it as simple as possible for him."
What will the game plan look like? It depends, Johnson said. Until this week, all his attention had been focused on Alex Smith. Now, he's trying to figure out Troy Smith's strengths and weaknesses so that he can call plays that suit his skill set.
Johnson is studying game film from Smith's days with the Ravens. (Besides his two starts, Smith played 12 times off the bench for Baltimore.) Johnson will also study his new quarterback in practice this week and talk to Smith about what plays he feels comfortable running.
A strong running game would help take the pressure off, but the 49ers insist that they won't be afraid to ride Smith's arm.
"We're not going to hide him," Johnson said.
Johnson was the Ravens' wide receivers coach in Baltimore in 2007. He said that back then, the rookie struggled with his footwork, drops and reads -- things that have been "cleaned up" since, Johnson said.
The thumbnail scouting report: "He's a competitive guy, a smart guy. He understands his job, and he understands how to manage a game."
Smith, the 2006 Heisman Trophy winner at Ohio State, was a prolific runner in college. He once had 11 rushing touchdowns in a season. But Johnson said there are no plans to have the quarterback running with the ball unless it's on play-action rollouts.
Of course, things could change.
"I've got three days to see what he does well and put a game plan together," Johnson said. "We're going to put him in the best possible situation."
For more on the 49ers, see Daniel Brown's Hot Read blog at blogs.mercurynews.com/49ers.