Hernandez has two years and $40.5 million remaining on his current contract, but those final two years will apparently be replaced by the new deal, which extends through 2019 and will make him the highest-paid pitcher in Major League history.
Hernandez was in Peoria to take his physical on Tuesday along with the rest of the Mariners pitchers and catchers, but returned to Seattle for the official signing.
"We're headed out right now and Felix will be headed out as well and we'll give you all the details at that time," Zduriencik said.
"I would send along my congratulations to [Hernandez's agents] Scott Pucino and Wil Polidor. They were very professional in working this agreement with us. I think it's a great thing for the Seattle Mariners and it's a great thing for Felix Hernandez. We're looking forward to this guy being here for a long time, obviously."
CC Sabathia of the Yankees currently has the largest overall contract for a pitcher, with a seven-year, $161 million deal he signed before the 2010 season. Zack Greinke signed the highest average-annual-value deal at $24.5 million with his six-year, $147 million contract in December with the Dodgers.
Hernandez, 26, has been with the Mariners his entire big league career and won the American League Cy Young Award in 2010. He pitched a perfect game last season while going 13-9 with a 3.06 ERA in 33 starts.
The three-time All-Star has pitched 200 or more innings in each of the past five seasons and has a career record of 98-76 with a 3.22 ERA.
Hernandez is still not expected pitch for Venezuela in next month's World Baseball Classic after deciding last week that the contract negotiations and new deal were his first priority.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.