The 27-year-old completed a £8million move from Old Trafford to The Hawthorns on Saturday on a four-year deal.
"I spoke to Fletch regularly. I rang him just after he had made the move here from United (in February) and he said how much he was enjoying his football," he told the club's official website.
"When West Brom came in for me, it definitely had an influence on me. I was able to speak to Fletch quite a few times and he assured me he was still enjoying it."