American men's professional tennis has enjoyed a long ride in the Top 10 ATP World Tour rankings for many years, decades in fact. At the height of dominance, the United States had produced tennis greats Arthur Ashe, Jimmy Connors and John McEnroe. That era was followed by one of the greatest – Pete Sampras, Andre Agassi, Michael Chang and Jim Courier. The torch has since been handed over to Andy Roddick, James Blake and the Bryans (Bob and Mike), but their prime tennis years may be nearing the end.

We've seen Roddick take some tough and unexpected losses this season, but in all fairness, it seems as if the dreaded "mono" bug bit Roger Federer last year, caught up to Roddick recently (no excuses). The light almost came on for Roddick last year at Wimbledon where he played his absolute best and still lost. Hopefully, he still has a few more spectacular and entertaining tournaments in him.

So what about the next generation of American tennis?

The future of American men's tennis does look a bit dim, but there is promise. Who can deny the heart of big John Isner and that historic first-round match at Wimbledon? Sam Querrey also seems to be coming into his own with some good tournament wins this season. Both of these young guns are hovering around Top20 and only time will tell if they've got the staying power.

Then there's the best of the rest. Mardy Fish often and frequently flirts with brilliance. He's gotten himself in great shape and with a little bit of confidence is always a threat during the summer hard court season. Matter of fact, Fish has just show that he's got the goods by defeating fellow Americans Roddick, Isner and Querrey in back-to-back tournaments leading up to the U.S. Open. Here's hoping that he stays healthy.

Further back in the pack is now-healthy Taylor Dent, along with Michael Russell. It's good to see Dent back on the court with a few match wins given all he's been through with his back troubles.

Unfortunately, we have to look past Top 100 to find the next group of players with potentially bright futures. Names including Donald Young, Robby Ginepri, Robert Kendrick and Kevin Kim have all been associated with the future of American tennis, but none have risen to the occasion. James Blake finds himself in with this pack as well, and he's got a lot of soul searching to do if he wants to right the ship anytime soon.

It does seem as if American men's tennis is in a bit of a lull. Roddick may be down, but he's not out. With a few good tournaments he should pull himself back up to Top 10. The next best hope is with Isner and Querrey, who still have plenty of time to make some noise. And while the Bryan's are no longer winning nearly every tournament they enter, they still own the No. 1 ranking.

Yes, the United States doesn't offer up as many dominant men's tennis players as it once did, but we more than make up with heart. You can expect to see that heart on full display at this year's U.S. Open.