But on this day, the American League Cy Young Award winner had one additional -- and very interested -- observer. Michael Pineda, the Mariners' prized 22-year-old rookie prospect, stood just off to Hernandez's side, and took in every move made by his talented teammate.
"He did that on his own," said Mariners pitching coach Carl Willis. "It's not that he's trying to go out there and learn how to be Felix Hernandez. It's more about watching how Felix does his work, the intensity of his bullpens, what he's trying to accomplish, and the quality of that work.
"It's not just, 'I've got to throw for 10 minutes, and go blow through it,' but to see how a Cy Young winner gets something out of it."
2010 Spring Training - null
Sights & Sounds
Spring Training Info
And regarding the fact Pineda, a powerful 6-foot-5, 247-pounder out of the Dominican Republic, took it upon himself to get a front-row view of Hernandez's routine?
"It's a great sign," said Willis. "He's hungry, he wants to learn, he wants to be the best he can be -- and he's got all the physical abilities. Like many of us, he still needs to learn how to play the game, and prepare to play the game."
The big right-hander said he's been talking to Hernandez as much as possible this spring, and took advantage of Monday's bullpen session for a little extra homework.
"I want to watch him because I want to have a changeup like Felix, you know? And a slider, too," said Pineda, who is learning English, along with the Major League routine.
Pineda, the 13th-ranked prospect in baseball by MLB.com, will make his first Spring Training start on Wednesday against the D-backs at their new Salt River Fields facility in a 12:05 p.m. PT contest.
Mariners catcher Adam Moore caught Pineda three times at Triple-A Tacoma last year, where Pineda started 12 games after dominating the Double-A ranks. Moore said the massive youngster is making swift strides, as he attempts to land a spot in Seattle's rotation this spring.
"His demeanor out on the mound and understanding of what he wants to do is impressive for a young guy," said Moore. "When you ask him what he's thinking, he has an idea of what he's doing with location and pitch selection. He's growing. And with that big body out there and his deception, he's going to be something special."
Infielder Brendan Ryan, acquired by the Mariners in an offseason trade with the Cardinals, didn't take long to learn what everybody was talking about when it came to Pineda -- who appears taller than his listed 6-foot-5, and has broad shoulders and a powerful build.
"He's an intimidating presence," Ryan said. "Throwing the ball that hard with some movement, it's a wonderful thing."
At least when he's on your side. Moore said while everyone sees the upper-90-mph fastball, Pineda's slider and changeup are impressive, as well.
"His changeup is looking really good," Moore said. "It comes out of the hand looking like his fastball, with the four-seam spin on it -- and it's got that late action, arm-side run to it. Once he's able to locate that pitch consistently, he's going to be something."
And the fastball?
"Straight downhill," said Moore. "It's a heavy ball. And it's getting there pretty quick."
The Mariners -- and D-backs -- will get a better feel for what Pineda's bringing to the table in Wednesday's debut. He'll likely pitch two innings. The Mariners are eager to get a first, live glimpse of their premier pitching prospect this spring, but remain cautious, as well.
"He's shown -- as all the guys have -- his stuff has been good. His command has been very good," said Willis. "But we've seen in the first couple of games, even with the veteran guys, they haven't competed in five or six months.
"The quality of our strikes isn't where they need to be. But we understand that as we go deeper into Spring Training, they're going to get better. They're just getting acclimated again to competing against hitters.
"So if he goes out and commands the baseball as he has in his bullpen sessions and batting practice, I think it's a good day. If that doesn't happen, it's not alarming by any means."
Either way, you can count on one thing. With Pineda pitching, this time there will be plenty of interested people taking notice of him. And the watch has only begun.