Steve Ballmer has written a letter to Microsoft's CEO, explaining that his new Los Angeles Clippers purchase will probably keep him so busy in the coming years that he has no choice but to leave the company's Board of Directors. Ballmer's resignation is effective immediately.

"As I approach the six month mark of my retirement and your appointment as CEO, I have been reflecting on my life, my ongoing ownership of Microsoft stock, and my involvement with the company. I have reached some conclusions and wanted to share them with you," wrote Ballmer in the letter to Nadella, "In the six months since leaving, I have become very busy. I see a combination of the Clippers, civic contribution, teaching and study taking a lot of time."

Ballmer has been with Microsoft for about 34 years and served as the company's CEO for more than a decade. Despite his deep involvment with Microsoft, he announced last August that he would step down within 12 months. He retired six months later and was succeeded by Satya Nadella. And now, six months after retiring as CEO, he has resigned from Microsoft's Board of Directors to prepare for teaching a new class and for the start of the NBA season.

Ballmer placed a bid of $2 billion in May to purchase the Los Angeles Clippers of the National Basketball Association, and he officially became the Clippers owner on 12 August. His departure from Microsoft's board isn't shocking however. Rumors have been circulating since January about whether Ballmer would eventually severe all ties with the company. But Ballmer hasn't completely put Microsoft in his rear-view mirror. He still owns 333 million shares, or about 4 per cent of the company.

"I bleed Microsoft - have for 34 years and I always will. I continue to love discussing the company’s future. I love trying new products and sending feedback. I love reading about what is going on at the company. Count on me to keep ideas and inputs flowing," Ballmer added. "The company will move to higher heights. I will be proud, and I will benefit through my share ownership. I promise to support and encourage boldness by management in my role as a shareholder in any way I can."

READ: Steve Ballmer admits Microsoft needs a new leader for faster change

Oh, and in case you missed the sound of Ballmer screaming like crazy at press conferences, check out the video below, where he is introduced as the new LA Clippers owner. Warning: You might want to turn down your device's volume.