The 20-year-old is currently on a on a 93-day loan deal at Championship strugglers Barnsley from his parent club Stoke City, who he joined for £3.5million in the summer.
But Clark believes the England international, who is yet to play for the Potters, quit the West Midlands club too soon.
"When Jack did the deal to Stoke, he probably didn't expect to be at Barnsley," Clark told the Daily Mirror.
"He went to Stoke with the thought of being a Premier League goalkeeper.
"Sometimes it is too early to leave. It is better to stay where you are for a while.
"But Jack didn't have that choice due to our financial situation."