"I liked what I saw," Johnson said. "I think he kind of turned it up a little bit, knowing he was going to be the starter this week."
Ready or not, Smith is being thrown to the fire with the decision of 49ers coach Mike Singletary to start him ahead of No. 2 quarterback David Carr. Starter Alex Smith is out at least two weeks with a separated left shoulder.
Here are excerpts of comments by Johnson about Troy Smith during a media session Thursday in Hertfordshire, England, east of London, where the NIners are preparing for Sunday's game against the Denver Broncos at Wembley Stadium:
On whether he had much influence in the decision to start Smith rather than Carr: "I don't know if I had much influence, but we talked about it. So I was part of the process, and it was something we decided to go with, and we have to make it work."
On what Johnson learned about Smith when he was on the Baltimore Ravens' coaching staff in 2007: "Well, he had to clean up some footwork things. He had to get better in fundamental areas, such as drops and reads and things like that, but I think from that point to now, I think he has gotten better, a lot better."
How he would describe Smith's strengths: "He's a competitive guy. He's a guy that's smart, he understands football, he understands how to manage the game. I'm still trying to figure out some of the things he does well, and watching him practice and now that I really have a chance to see what he can do and put a game plan together, so I'm still learning basically what he does well also."
On what they're focusing on this week given the short notice about Smith: "Well, he has to go in there and play. He's got to go in there and make enough plays for us to win this game, and that's going to be my job and our job as an offensive staff is to put together a game plan where he can be effective. We're not going to hide him. He's going to go out, and he's going to play, and he's going to be the quarterback for the San Francisco 49ers."
On whether they'll stick with the same game plan as if Alex Smith were starting or will do some things differently: "You have to do a couple of things different. First of all, we have to take more reps to get him prepared better, so we have to practice more on offense. We have to do certain things there, but for me personally, it's a week where I get three days to kind of see what he does well, and then put (a game plan) together. Our main thing anyway is that we have to run the ball efficiently (and) effectively enough to set up our run-action pass, to set up our naked bootlegs, to set up what we do on our third-down run games. That starts every week at the same place and then we go from there. Some of the things we'll do differently with Troy."
On what he saw in Smith during practice that he hadn't seen previously: "I think he was just more focused. Definitely detailed in his fundamentals, footwork, running the huddle and making sure everything is right from that standpoint. He was definitely better yesterday."
On whether Smith is better using his feet than either Alex Smith or David Carr: "He is definitely a good athlete, but that's not something we're designing and putting together. We're not putting together an offense where Troy Smith is going to run the ball. We're trying to put together an offense where we can be effective both running and passing, starting with (RB) Frank Gore, (TE) Vernon Davis, and (WR) Michael Crabtree, and then he has to distribute the ball to those people and let them make plays."
UPDATES: Vernon Davis (ankle) did not take part in practice, but he's still expected to play Sunday. Taking part in limited practice: RB Anthony Dixon (hamstring) and CBs Nate Clements (ankle) and Tarell Brown (back). LB Ahmad Brooks (knee), who sat out Wednesday, was a full practice participant. … Safety Chris Maragos, who was waived on Wednesday to make room on the roster for CB Tramaine Brock, was signed to the practice squad.