ROQUEBRUNE, France (AP) France captain Guy Forget picked injured Gilles Simon to play singles against John Isner of the United States in the Davis Cup quarterfinal.

Although the 13th-ranked Simon is nursing a sore back and had little practice, Forget selected him Thursday ahead of lower-ranked Julien Benneteau and Michael Llodra.

Sixth-ranked Jo-Wilfried Tsonga will open on clay against 19-year-old American Ryan Harrison at the Monte Carlo Country Club on Friday.

I've been in his position before, and I know you can be easily inspired when you're at that age,'' Tsonga said.There will be a lot of emotion and it depends how he handles that.''

Simon replaced the injured Gael Monfils. He is 0-2 against Isner, one of the game's biggest servers.

Isner recently beat Simon at Indian Wells, but feels that win will count for little.

I don't think it's going to make that much of a difference,'' Isner said.It's Davis Cup. It's a whole different animal than a regular tournament. (Simon's) going to take to the court very confident.''

American captain Jim Courier is without Mardy Fish, who pulled out with fatigue this week.

We're very prepared. We have a great team, a great coach and captain,'' said Harrison, whose only Davis Cup appearance came in the meaningless reverse singles during the 5-0 sweep of Switzerland in February.I think we're as prepared as can be.''

Brothers Bob and Mike Bryan will play Benneteau and Llodra in the doubles on Saturday. In reverse singles on Sunday, Isner opens against Tsonga and Harrison faces Simon.

It's a luxury to have Bob and Mike. It was a luxury I never had when I was a playing member of the Davis Cup team,'' Courier said.We tended to scrambled singles players together, and we didn't do very well. I have the utmost confidence in them.''

The Bryans know not to discount the French players. France's victory in the doubles four years ago handed the Bryans only their second loss in Davis Cup, and they have not lost since. Llodra - who played alongside Arnaud Clement against them in 2008 - also played doubles against the United States in the 2002 semifinal, which France won 3-2.

This is one of the toughest teams we'll be facing,'' Bob Bryan said.Llodra has been one of the biggest rivals over the last 14 years we've been playing. (We've) played him in big matches all over the world. This is another big one, we're expecting another tough match.''