John Isner, a towering figure at 6-9, is ranked No. 11 in the world and the top seed in the Delray Beach International Tennis Championships this week. Andy Roddick has slipped to No. 30 — his lowest ranking in a decade — and is the fourth seed. Nevertheless, Roddick remains the most commanding American figure in men’s tennis as he approaches his 30th birthday this summer.

When he shows up at a tournament on U.S. soil, reporters seek him out, and fans gravitate toward his practice court. That was the case Monday morning at Court 3 of the Delray Beach Tennis Center. Roddick filled the media in on his latest injuries, his frustrations, his source of motivation and his radio show. He then gave fans something to Tweet about as he hit with No. 5 seed Philipp Kohlscreiber.

Roddick is scheduled to play his opening match Tuesday night, not before 9 p.m., against Philipp Petzchner of Germany. If he wins, he faces a rematch with Denis Istomin of Uzbekistan, who knocked him out of the quarterfinals 6-2, 6-4 at the SAP Open in San Jose, Calif., two weeks ago. Roddick was recovering from a partial hamstring tear in his right leg, had injured his right ankle in his first match there and was so upset with how he was playing he slammed two rackets.

If Roddick gets by Istomin this time, he could face Xavier Malisse, who knocked him out of the Memphis tournament in the first round last week, 7-6 (10-8), 7-5.

His immediate goal is “getting into a flow again,” and playing near the Boca Raton courts where he grew up might be the perfect spot. He said he is unconcerned with his ranking. The struggle has been deciding whether to rest the nagging injuries or play through them.

“Frankly, I’ve been home too much the last eight months, and I’m a little sick of it. I want to feel like a tennis player again. Walk into a tournament, play a match and have it be second nature. It’ll just take one event to turn it. It’s happened before, and I’m confident it will happen again.”

He firmly believes he could contend for major titles again.

“I have a long way to go to get even close to level those top four guys are playing right now, that’s just being real,” he said. “That being said, do I think I can get hot and serve my way deep into a slam? Yeah. I do. All you want is a chance. I certainly think that’s a realistic possibility.”

The struggle motivates him.

“The thing in sports, there’s no script,” he said. “In the entertainment industry, you win an Oscar you’re viewed a certain way for 40 years. Sports, what makes it exciting, genuine and real is the fact you have to be better than a person on any given day. Doesn’t matter how good you’ve been throughout your career.”

If Roddick advances to the semifinal Saturday, he will have to skip the nationally syndicated radio show he does with Austin radio personality Bobby Bones. Roddick said he’s enjoying the part-time gig. “I don’t know a thing about radio, but I’ve never been shy about opinions and I guess that is half the battle,” he said. “It’s no different from the normal way I spend my Saturday afternoons, talking sports, but I just have an audience.”

Isner plays his opening match against wild card Jesse Levine of Boca Raton on Tuesday afternoon. Ivan Lendl and Carlos Moya play the Champions Tour final at 7 p.m. Tickets are available at 561-330-6000 or at yellowtennisball.com.