The changes worked.
"I thought that was the best he's thrown in a while," manager Jim Leyland said.
Jones said he watched Verlander throw on the sidelines and reviewed films of his games for the past couple of years, searching for the answer as to why the Tiger right-hander has been struggling this season.
What Jones discovered was that Verlander's front arm was "getting higher and higher."
"Justin has a great feel for when he does something wrong," Jones said. "But he didn't feel this one."
"I felt my fastball command was much better right out of the gate," Verlander said.
Jim Hawkins is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.