The Seattle system is stocked with talented young arms capable of joining Hernandez within the next year or two, highlighted by three of MLB.com's top 61 prospects.
The most highly-touted are right-hander Taijuan Walker and lefty Danny Hultzen, MLB.com's fifth- and 18th-ranked prospects, respectively. Walker, 20, struggled at Double-A during last season's second half, but his three-pitch repertoire and athleticism make him one of the game's most exciting youngsters.
Hultzen, 23, was lights-out at Double-A in 2012 -- going 8-3 with a 1.19 ERA in 13 starts -- but struggled at Triple-A, posting a 5.92 ERA in 12 outings. Despite Hultzen's Triple-A numbers, there's every reason to believe the No. 2 overall Draft pick in 2011 will reach Seattle at some point this season.
The same goes for lefty James Paxton, the club's No. 5 prospect and No. 61 overall, who could challenge for a rotation spot in Spring Training. The 6-foot-4, 220-pounder has a power arm (10.6 strikeouts per nine innings in his pro career) and a nice curveball. If Paxton can develop his changeup and command (4.3 walks per nine innings), he also could break north with the big club.
There are other high-ceiling pitchers in Seattle's system -- right-handers Stephen Pryor (No. 6), Carter Capps (No. 7), Victor Sanchez (No. 9) and Brandon Maurer (No. 10) -- and the Mariners appear to have the perfect young backstop to handle their talented rotation.
Mike Zunino (No. 3), the third-overall pick in last year's Draft, posted a .360/.447/.689 line with 13 home runs in 44 games between two levels in his first professional campaign. A seasoned college catcher out of Florida with power and advanced discipline at the plate -- and an accurate arm behind it -- Zunino soon could make a Major League impact.
"He's definitely well ahead of most college players who come out," Minor League coordinator Chris Gwynn said. "Receiving-wise, I think he still has stuff to learn. Offensively, he's pretty good now. But he's only had  at-bats in the Minors.
"That makes me nervous, in the sense that, are we really preparing him for when he gets here? He still has stuff to learn both ways, but catching is such an important position, you need to make sure he's well-seasoned before he shows up here."
Top 20 prospects
Behind Zunino at No. 4 among the Mariners' top prospects is shortstop/second baseman Nick Franklin, who also could reach Seattle at some point in 2013. Franklin, a switch-hitter with good speed and instincts on the bases, split last season between Double-A and Triple-A. Other high-impact position players in the Mariners' system are shortstop Brad Miller (No. 8), who hit .334/.410/.512 with 15 homers at Advanced Class A and Double-A last season, while second baseman Stefen Romero (No. 12) put up similar numbers (.352/.391/.599 with 23 homers) at the same levels. Though only 19, outfielder Gabriel Guerrero (No. 11) -- Vladimir Guerrero's nephew -- has the power his last name suggests.
While Maurer doesn't receive the attention of the Hultzen/Paxton/Walker trio, he was the most consistent of the quartet last season while together in Double-A. The 22-year-old righty has four pitches he can throw for strikes and was 9-2 with a 3.20 ERA in 2012.
Under the Radar
Right-hander Carson Smith, the Mariners' eighth-round pick in 2011, had a very nice first season at Advanced Class A High Desert. The 23-year-old was 5-1 with a 2.90 ERA and 15 saves in 49 appearances, striking out 77 in 62 innings.
Seattle acquired outfielder Leon Landry and righty Logan Bawcom from the Dodgers in last year's Trade Deadline deal involving reliever Brandon League. Landry, 23, was a third-round pick in 2010 who has great speed, hitting 18 triples and swiping 27 bases combined for both organizations last season. He also posted a .341/.371/.584 line.
Hitter of the Year
Assuming Zunino spends a good chunk of the season in the Majors, the middle-infield trio of Franklin, Miller and Romero seem to be the leaders for this award. But don't count out Guerrero, who put together a .349/.393/.593 line with 15 homers in 68 games in the Dominican Summer League and the Arizona League last year.
Pitcher of the Year
In a system full of impact arms, any number of pitchers could come away with this title. Walker is probably the favorite based on stuff and upside, though Hultzen, Paxton and Maurer likely will have their say in the race.