Querrey filling in for Fish

Querrey was the answer.

Sam Querrey, the 22-year-old Californian who has moved up to 25th in the men's world tennis rankings and to second behind Andy Roddick in the United States, is the newest addition to the IcyHot Chattanooga Challenge exhibition Thursday at McKenzie Arena.

Querrey is replacing Mardy Fish as 6-foot-9 John Isner's opponent in singles play and his partner against the top-ranked Bryan twins, Bob and Mike, in the highlight match. Isner is the third-ranked U.S. male singles player and a frequent Querrey doubles partner.

"Mardy had knee surgery a while back but was back in training and suffered a setback," said Atlanta-based promoter Trevor Short. "He just wasn't able to play. But I know Sam pretty well -- he's been in some of my previous events -- and he agreed to step in. It's really an upgrade. He and John both beat Andy this year."

Querrey won ATP tournaments last year in Las Vegas and this year in Los Angeles and had four runner-up finishes in 2009, when he was the US Open Series winner.

Short was able to line him up for all four cities in the Bryan twins' Southern tour -- in Birmingham on Wednesday, Chattanooga on Thursday, Atlanta on Friday and Nashville on Saturday.

Short had to come up with four replacements for Melanie Oudin's scheduled opponent, top-ranked American junior Sloane Stephens. She has a broken wrist.

A highly regarded nearby collegian in each city will face Oudin, the Marietta teen darling of Wimbledon and the U.S. Open who has Chattanooga relatives. At McKenzie it will be the University of Tennessee's Caitlin Whoriskey, who won the ITA Ohio Valley Regionals last month and is one of three women on the U.S. team headed to international competition Dec. 9-14 in Poitiers, France.

Oudin and Whoriskey will square off in one set at 6 p.m. Thursday, followed by Querrey against Isner in a two-setter with a super tiebreak if needed. Then local teens Nathan Schley and Zachary McCormick will have a short match with the Bryans before the twins take on Querrey and Isner.

Tickets cost $49.50 and $69.50 through www.tickettracks.com or TandSevents.com. A few $150 courtside seats remain available, Short said.