Waghorn, who is one of the best players at Rangers, worked with Ball at Sunderland.
The 26-year-old started his professional club football career at Premier League outfit Sunderland.
The forward subsequently moved to Leicester City and Wigan Athletic before joining Scottish giants Rangers in the summer of 2015.
The former England Under-21 international forward has expressed his gratitude towards Sunderland coach Ball.
“I put all my success down to Bally to be honest,” Waghorn told Sunderland’s official website. “I was close to being released at 15 before my scholarship and throughout everything he just kept me so grounded.
“Before I made my debut I remember he took me to one side and we had a coffee, and he told me not to get ahead of myself.
“He reminded me that I was a young boy and that I would be coming back down to train with the under-18s once I had made my debut.”
“He kept me really level-headed, made me work harder and harder and looking back now he could see that I could go further and further,” added the Rangers forward.
Waghorn would have scored more goals for Rangers this past season had he not suffered an injury.
The Englishman will be a key player for the Gers in the Scottish Premiership next season.
It will not be easy for the forward to bang in the goals like he did in the Scottish Championship, but one suspects that he is looking forward to the challenge.
Rangers will be aiming to compete for the Scottish Premiership title with Old Firm rivals Celtic next season.