According to multiple sources, Krook has opted to pitch for the University of Oregon rather than sign with Miami.
Technically, teams have until July 12 to sign all of their picks, but sources say there is no chance Krook will be swayed. The slot allotment for the No. 35 pick is $1,587,700.
Krook, who attended St. Ignatius High School in San Francisco, was a Competitive Balance Round A pick. The Marlins obtained the pick, along with Gorkys Hernandez, from the Pirates last July in exchange for Gaby Sanchez.
Although Krook has decided to play college ball, the Marlins have not been left empty-handed, as they will receive the 36th overall pick in 2014.
The Marlins have already reached agreement -- or are near agreement -- with seven of their top 10 picks.
Still unsigned is first-rounder Colin Moran, the third baseman from the University of North Carolina who was taken No. 6 overall.
The Marlins are aggressively trying to sign Moran. Contract talks began after North Carolina was eliminated from the College World Series a few days ago.
The allotment for Moran is $3,516,500.
Miami also is negotiating with second-rounder Trevor Williams, a right-hander from Arizona State.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro. This story was not subject to the approval of Major League Baseball or its clubs.