Arlen Kantarian, the man behind the U.S. Open Series, blue courts, the women’s prime-time final and instant replay, announced his resignation today, confirming rumors that had been swirling for months. (I mentioned it in a posting here on Oct. 16).

Hard charging, shrewd and focused on dollar signs, Kantarian played a part in many of the innovations that helped the U.S. Open become the blockbuster event it is today – purportedly the largest attended event in all of sports.

“I have enjoyed one of the finest rides in sports and entertainment for the last 25 years,” said Kantarian, 55, in a statement issued by the USTA. Nine of those years were spent at the USTA; the others were with Radio City and the NFL.

It’s hard to argue with Kantarian’s record. Instant replay has been a near-unanimous hit. The nighttime women’s final has boosted TV ratings. Many tournaments have adopted bi-colored court schemes and, whatever you think of the U.S. Open Series, it has brought some coherence to the summer schedule even if it has not been an unalloyed success.

More importantly, he was instrumental in increasing revenues at the U.S. Open by $70 million and grew attendance to more than 720,000 in 2008 – 150,000 more than when he arrived in 2000.

“He’s one of the most outstanding executives in all of sport,” said Franklin Johnson, the former USTA chairman and current board member.

However, it would be overly simplistic to say Kantarian is riding out to the sunset in a blaze of glory. Little was said about why Kantarian decided to depart (it takes effect at year-end), and he declined to specify in news reports.

The full explanation of his exit will probably come out in the days and weeks to follow, but certainly there have been whispers for a while about his management style. Kantarian was known as a tough negotiator, to the point of being a pain in the rear. He carried a fat salary, which could have been a sticking point in the ongoing contract negotiations. Sources in and outside of the USTA also say that some felt he had consolidated too much power through the years and that some of the newer board members and executive staff wanted to split off some of his responsibilities. Others say he often clashed with personnel.

Whether he wore out his welcome or not, Kantarian surely had many supporters within the USTA who were sad to see him go.

“Arlen has had an unbelievable run for the USTA,” said Patrick McEnroe, who Kantarian hired to head up the USTA’s elite development program, which Kantarian had overseen since 2007. “He turned around the image of USTA with players, agents and TV people. He set us up to have more success in future. No one can argue with the kind success he’s had.”

Kantarian will help in the succession plan, the USTA statement said. The new head of pro tennis will have difficult act to follow considering how much the U.S. Open has grown. Besides the obvious duties of keeping TV rights holders and sponsors happy, the goal for his replacement should be to maintain the level of attendance, revenue and status it has achieved. Other priorities should be the ongoing exploration of a retractable roof of some kind and making sure that McEnroe continues to get the financial and organizational support he needs to make significant inroads in player development, which has bottomed out in recent years.

Canny to the end, Kantarian might have outmaneuvered the USTA by orchestrating his exit now. Considering the bleak economic outlook and what he had already accomplished, there wasn’t much more he could do.