The player makes a swing at the ball which is teed up in the teeing area. Before he makes contact, the ball blows off of the tee.
I think he has to count the stroke for the miss and then play it as it lies.
There are a couple of rules, but none that covers this exact scenario:
11-3. Ball Falling off Tee
If a ball, when not in play, falls off a tee or is knocked off a tee by the player in addressing it, it may be re-teed, without penalty. However, if a stroke is made at the ball in these circumstances, whether the ball is moving or not, the stroke counts, but there is no penalty.
ALL FALLING OFF TEE
Stroke Misses Ball; Ball Then Accidentally Knocked Off Tee
Q.A player teed his ball within the teeing ground. He made a stroke at the ball but missed it. He addressed the ball again and accidentally knocked it off the tee. What is the ruling?
A.When the player made a stroke at the ball, it was in play and Rule 11-3 no longer applied. When the ball in play moved after it was addressed, the player incurred a penalty stroke and was obliged to replace the ball (Rule 18-2b).