Simpson, signed from Arsenal for an undisclosed fee in the summer, has yet to score for Hull and Swan has urged fans to rally behind the 22-year-old.
Swan told the Hull Daily Mail: "Simpson now needs the fans to get behind him more than ever.
"Having seen him fail to score a goal in 15 games for the Tigers, I'm starting to feel sorry for him.
"He badly needs the ball to go in the back of the net but it's now looking as if he's forgotten how to score.
"If he worked as a builder or in an office, he'd soon be looking for a new job if he failed to remember the basic principles of why he was employed in the first place."
Source: PA
Source: PA