Jenson Button has said that Lewis Hamilton's decision to switch to Mercedes next season is a blow for McLaren, although he is confident the Woking-based team will adapt.

News of Hamilton's defection came at the end of September, along with confirmation of his replacement, Sergio Perez, and speaking to reporters ahead of this weekend's Abu Dhabi Grand Prix at the Yas Marina Circuit, Button added he believes the current Sauber pilot will do a good job.

"Obviously it's very difficult to know what he brings to the team, because he's not there yet," Button said in the countdown to the 18th round in the 2012 F1 World Championhip.

"With Lewis leaving, obviously the team loses a very fast driver, a guy that's achieved a lot with the team, wins and obviously a World Championship - the last guy to win a World Championship for the team. It is a big loss but things change and you learn to move on and adapt. It's definitely not the end of two strong drivers at McLaren.

"I think Sergio will be fast but I really don't know. He's obviously unknown in a McLaren, because he's not there yet.

"But it's a great opportunity for Checo and I'm sure he will take it with both hands."

Button meanwhile rejected suggestions that he will take on an 'older brother' role in 2013, although he will clearly be the team number one.

"I was surprised when I was told Sergio was 22-years old. It seems like he's been around for a lot longer than that. But no, I don't feel like an older brother," explained the 32-year-old.

"It's important to work closely with your team-mate. I think that when he's in the team he will probably learn a lot from someone who is older, with more experience, which is me, but I still think that when you're an older driver you can still learn from a younger teammate [too], because they will bring fresh ideas to the table as well. But as an old brother? No, I definitely don't feel like that..."

As for if Hamilton will be able to help Mercedes go forward in 2013, JB added that it is difficult to say: "I really don't know. I think the first year with a new team is always a little bit tricky. It's a new experience for Lewis. I'm sure he's excited about it. But I really don't know.

"He's as quick as they come but sometimes it's not that easy to win grand's prix and to build a team around you and also to help a team achieve great results," Button warned.