Nightengale also reported the deal "should be finalized before spring training," which officially begins on Monday, Feb. 11.
UPDATE: Saturday, Feb. 9, at 12:55 p.m. ET by Alex Ballentine
MLB.com's Greg Johns reports that the Mariners and Hernandez's agency have denied reports that any contract extension has been finalized. Additionally, Hernandez will skip the upcoming World Baseball Classic while negotiations remain ongoing.
According to a representative from the agency that represents Hernandez:
We still have not reached an agreement, but we are moving forward... At this moment, we have covered 70 percent of the road
---End of Update---
UPDATE: Thursday, Feb. 7, at 7:57 p.m. ET by Tyler Conway
ESPN's Buster Olney comes in with the latest details on Hernandez's contract. The Mariners ace's extension is for five years and $135.5 million, with his annual salary making him the highest-paid pitcher in MLB history:
Considering how brilliant Hernandez has been over a long period of time, this deal is well deserved and should set the bar for elite pitchers going forward.
---End of update---
UPDATE: Thurs. Feb. 7, at 3:30 p.m. ET by Adam Wells
Greg Johns of MLB.com is reporting that there is no agreement in place between the Mariners and Hernandez at this time, nor is an announcement imminent.
The Mariners have no announcement of a Hernandez contract extension planned at this time, according to a club spokesman.
Until a deal becomes official, Seattle isn't going to say that anything is done. It's just the nature of contract negotiations. Regardless, the two sides could be very close.
---End of update---
Hernandez's extension would make him the highest-paid pitcher in baseball history, both in terms of total value and average annual salary ($25 million).
Hernandez had two years left on his five-year, $78 million extension that he signed in 2010.
The Mariners have made re-signing Hernandez a priority this offseason. This should not come as a surprise, as he was coming off one of his best seasons in 2012. He finished fourth in the American League Cy Young voting behind David Price, Justin Verlander and Jered Weaver.
Hernandez pitched 232 innings in 2012, his fifth straight season with at least 200 innings. He also finished the year with a 3.06 ERA and 223 strikeouts, marking the fourth straight year he's struck out at least 215 batters.
His greatest accomplishment of the 2012 season came on Aug. 15, when he threw the first perfect game in franchise history against the Tampa Bay Rays. The perfecto was one of Hernandez's five complete game shutouts in the year.
At age 24, Hernandez won the 2010 AL Cy Young award after throwing a career-high 249.2 innings and posting a league-leading 2.27 ERA with 232 strikeouts. Though he hit a bit of a rough patch in 2011—at least by his standards—he has remained an elite starting pitcher since his breakout campaign in 2009.
Hernandez's domination is even more impressive when you consider that the Mariners haven't put together an offense that has finished higher than 26th in runs scored since 2007. Last year, only five qualifying starting pitchers had less run support than "King Felix."
This could be the beginning of big things for the Mariners, who are loaded with starting pitching in their farm system. With Hernandez leading the rotation and Taijuan Walker, Danny Hultzen, Brandon Maurer and James Paxton all coming up the pipeline, they could have one of the best pitching staffs in baseball in a few years time.
After missing out on free-agent targets like Josh Hamilton and Prince Fielder a year ago, the Mariners needed to make a splash to generate interest in their franchise. They added some power to their lineup by acquiring Kendrys Morales and Michael Morse through separate trades, but lacked a signature offseason move.
Securing a franchise player like Hernandez for the long term would go a long way.