Originally Posted by themanmachine
If I grab the left arm and move it, I can feel the slightest amount of play in either the bottom bracket or the crank arm.
Is this lateral or rotational play? Does the left crank arm move while the right does not? If so, the crank interface is probably rounded out. If both cranks move laterally, your bottom bracket is probably loose.
Also, have you investigated other noise sources? Check your chainring bolts and your pedals.