INDIANAPOLIS — Andrew Luck has signed a new contract with the Indianapolis Colts that covers the next six seasons through 2021.

The $140 million deal was completed Wednesday with Luck, the No. 1 pick in the 2012 draft. Owner Jim Irsay revealed the maximum value on Twitter, calling it the biggest contract in NFL history.

Luck has been one of the most productive quarterbacks the NFL has ever had over a player’s first four years as a pro. He was the third-fastest to 13,000 career passing yards, in 49 games.

Before last season, the Colts exercised the fifth-year option on Luck’s contract to guarantee him more than $16.1 million for the 2016 season. The new deal adds five years, giving Luck another chance to cash in with a big contract around age 32.

JAMES HARRISON wants the NFL to provide “credible evidence” before he agrees to an interview with league officials regarding a media report that linked him and other players to the use of performance-enhancing drugs.

The NFL Players Association sent a letter on behalf of the Pittsburgh linebacker to NFL executive Adolpho Birch asking for more information.

“We have repeatedly requested that the NFL inform him and the NFLPA whether the NFL possesses any credible evidence (e.g., verified documents or verified testimony of witnesses) that warrants an interview of Mr. Harrison regarding a potential violation,” union attorney Heather M. McPhee wrote.

The other active players implicated by the Al-Jazeera report are Green Bay linebackers Clay Matthews and Julius Peppers, and free-agent linebacker Mike Neal, who played the past six seasons with the Green Bay Packers.

The NFL first notified Matthews, Peppers, Harrison and Neal about its investigation into the report on Jan. 11.