Playing wrong ball

Question
QUESTION: My playing partner and I both hit good drives down the middle of the fairway. The balls ended up close together and there were no other balls to be seen. He then played "his" ball which he hit deep into a bush - lost! When I came to play my ball it turned out to be his. What is my position?

ANSWER: John,

You place a ball on the position it was in before your playing partner hit it. No penalty to you but there is to your playing partner. He incurs a two shot penalty and must play from where his ball lie.

Rule 15

Thank for the question,

Michael

---------- FOLLOW-UP ----------

QUESTION: Michael many thanks for your answer, however my concern is that I obviously didn't identify the lost ball as mine before it was played. Is it therefore OK to assume that it was without definite identification?
Thanks again.

Answer
John,

Two players hit their drives in the middle of the fairway close to one another. Your playing hits a ball thinking it was his. He hits the ball into a bush - lost. You then realize that the ball he hit was not his. Under the rule of equity you would not have to identify your ball.

Thank you,

Michael