The history of the Sharks can be split into two eras: Before Joe Thornton, and after Joe Thornton.

It’s befitting of a man nicknamed “Jumbo,” as San Jose’s acquisition of the probable Hall of Famer from the Boston Bruins on Nov. 30, 2005 marks the biggest turning point in the franchise’s history. The Sharks were no longer "up-and-coming” after the Thornton trade: His arrival meant they had arrived.

Thornton’s presence began an era in which San Jose climbed to the NHL’s elite, in large part on the back of his superstardom. Let’s examine the case for, and against, the Sharks retiring Thornton’s No. 19 jersey first. 

The case for

Save for Brent Burns’ run on defense over the last handful of seasons, no Shark has been as dominant at their peak as Thornton. He remains the only San Jose player to win the Art Ross and Hart Trophies, leading the league in scoring and winning MVP honors in the season he was traded to the Sharks. 

Thornton owns three of the four 90-point seasons in Sharks franchise history, scoring 92, 114 and 96 points, respectively, from 2005-06 through 2007-08. The fourth belongs to Jonathan Cheechoo, who led the league in goal-scoring in 2005-06 with 56 goals. Forty-nine of those goals came after Thornton was acquired. 

Cheechoo, Devin Setoguchi, Patrick Marleau, Joe Pavelski and even Burns all took their goal-scoring to the next level playing on Thornton’s wing. He is one of the best passers of all time, and his dominance is reflected on the Sharks’ all-time scoring charts: Thornton owns eight of the 10 highest single-season assist totals in San Jose history, and is 206 helpers clear in first place on the team's all-time list. 

Despite his absence on the NHL’s list of its 100 greatest players of all-time, Thornton simply is one of the best to ever play the sport. He’s the best player in franchise history, and his best years came in San Jose. This should be an open-and-shut case.