The NFC West side, who have won their last four games in a row, face the Jags at Wembley on Sunday.
The quarterback told reporters: "This team has a lot of work to do still. We have a lot to prove still. So, going into Sunday I don't think it matters what team we're playing, we're going to be motivated.
"They're a talented front. They do a lot of things well. They're very aggressive. They play hard. They play fast. Our offensive line is going to have to be on top of things this week.
"I think they are over-looked. Same way the Cardinals defense was over-looked last year. They had a good defense they just couldn't get wins. So, I think this is a similar defense where they're a good defense they just haven't quite put everything together."
The sides meet at Wembley on Sunday.