Vinik, 50, is purchasing Tampa Bay Sports & Entertainment from a group led by Oren Koules and Len Barrie, the team said. The deal is contingent on approval from the league’s Board of Governors, which is expected in three to four weeks.

“I’ve been an avid hockey fan my whole life and I pledge to our fans that I will work my hardest to build the Lightning into a world-class organization both on and off the ice,’’ said Vinik, who will have sole control.

Vinik, a financier, agreed to buy the team, the company that operates the St. Pete Times Forum, and 5 1/2 acres of land adjacent to the downtown arena. Financial terms were not disclosed, however it’s believed to be substantially less than the $206 million OK Hockey paid in June 2008.

Prior to being purchased by Koules and Barrie, the Lightning had been owned since 1999 by Palace Sports & Entertainment, a group led by the late Detroit Pistons owner Bill Davidson that helped transform Tampa Bay from a perennial last-place team into the 2004 Stanley Cup champion.

“The day is a bittersweet one for us, as I believe we have established a strong foundation on the ice and begun to point things in a positive direction for the Lightning,’’ said Koules, chairman of OK Hockey. “We look forward to seeing Jeff take the team from here and move it forward.’’

Vinik, who managed Fidelity’s Magellan Fund before founding Vinik Asset Management, is expected to be formally introduced as owner and officially take control of the team when the sale closes in a few weeks.

In the team statement, Vinik called purchasing the franchise a “dream come true.’’

“I hope to bring a high level of excitement and intensity back to Lightning hockey, with a goal of having the team consistently compete for the Stanley Cup,’’ Vinik said. “I have a passion for the game and will do my best to restore a winning culture . . . that all of our fans and partners can be proud of.’’