Sounds like you may be picking it up with your right hand (assuming you are a RH golfer) instead of taking it back low. Focus on your left hand and wrist pushing the putter head back and then staying slightly ahead through impact. You could also practice just using your left hand to make slow and low swings, back and through. Hope that helps...pm
I don't agree with this advice....
How low? And how slow?
Pushing back with the left hand will generally close the putter face,
Taking it back low extends the arm at the elbow or worse at the shoulder, which opens the putter face,
Taking it back slow interrupts his normal timing which may or may not help, but will generally change his mechanics,
Keeping the left wrist 'ahead' through impact is an opening of the clubface move, as well as a timing change,
All these clubface and timing micro adjustments COMBINED with a looping stroke .... hmmm
I wouldn't hope too much!
Bill,
Set up(without a putter) standing in your bent over putting posture(reasonably relaxed)...let your arms hang. Fit your putter to that posture first.
Then make strokes whereby you key into your timing, first without a ball, then with(but without a target).
Are you still looping?
Damon