The most difficult job on the team might belong to catcher Rob Johnson, and he had the bruises last season to prove it, darting every which way to keep pitches Hernandez threw in the dirt from skipping to the backstop and advancing runners.
As it was, Hernandez shared the American League lead with Yankees right-hander A.J. Burnett for most wild pitches -- 17.
"I love catching him, but it's very difficult," Johnson said. "Felix doesn't throw a pitch straight. Ever. You just never know what it's going to do, but it was an honor catching someone of that stature."
Hernandez, who had a breakout season in 2009, posting a 19-5 record, 2.49 ERA and finished second to Royals right-hander Zack Greinke in the AL Cy Young Award balloting, throws a two-seam fastball that rarely sinks the same way two times in a row, a four-seam fastball that sometimes acts like a cutter, a changeup that breaks straight down or moves left or right, a slider that backs up or breaks straight down, and a curve that's liable to break sideways or straight down.
"It has been such a good experience for me," Johnson said. "I have never caught anybody like him. No one is even close, stuff-wise."
Mariners pitching coach Rick Adair understands where Johnson is coming from.
"I don't even like standing in [the batter's box] when Felix is doing his side work," Adair said. "Imagine what it's like in a game with the adrenaline flowing. Rob will come into the dugout between innings and say, 'Rick, this is ridiculous.'
"You call for a two-seamer, which is supposed to sink, and you get a 95-mph pitch that cuts. Almost every pitch Felix throws has unbelievable movement. If you grade his four pitches on a scale from two to eight, all four of them are seven or eight. It's not easy to catch him."
Hernandez tells the story of the time last season when Johnson went to the mound to question a pitch Felix had just thrown -- perhaps one of the 17 wild pitches.
"He said, 'Man you were supposed to throw a four-seamer and you threw a two-seamer.' I told him, 'it was a four-seamer.' Another time, a ball hit him right on the end of his shoe and hurt his toes. He limped out to the mound to talk to me.
"He makes me laugh."
All kidding aside, the Hernandez-Johnson battery worked unbelievably well last season.
Johnson started 23 of Felix's 34 starts last season and 15 of Hernandez's wins (and just two losses) came with Johnson, a Montana native, giving the signals. The tandem allowed just 2.01 runs per game over 178 2/3 innings.
"He's very smart and we just seem to think alike," Hernandez said. "Every time he calls for a certain pitch, I am thinking the same thing. I almost never shake him off."
The 2009 season was nearly two months old before manager Don Wakamatsu decided to go with the Hernandez-Johnson battery on a regular basis.
Felix had just come off his worst start of the season, a 5 2/3 innings debacle against the Angels at Safeco Field on May 19. The skipper openly criticized his pitcher for lack of effort against the division rivals and had a meeting with Hernandez the following day.
Johnson, who had caught three of Felix's four wins, started behind the plate against the Giants and Hernandez surrendered one run over eight innings, ending a personal three-game losing streak
A match was hatched and Felix reeled off seventh consecutive wins.
"It wasn't by design," Wakamatsu said. "A lot of it had to do with the timing of some injuries. Kenji [Johjima]was hurt twice early in the season and in the meantime Rob and Felix had a nice stretch going. I didn't want to break that up."
Johjima was on the disabled list from April 16 to May 1 with a pulled right hamstring and from May 26 to June 26 with a broken left big toe. When he returned, Johnson was firmly entrenched as Hernandez's primary receiver.
Why did the Hernandez-Johnson tandem work so well?
"Rob is assertive and I think Felix needed someone like that," Wakamatsu said. "They built a trust in pitch selection. Once they clicked on that, and Rob would catch him, the comfort level increased.
"We preach from Day 1 that pitchers need to call their own game, but when a guy is putting down the same sign for a pitch the pitcher is thinking of throwing, there is a comfort level that goes with it."
And you can look for more of the same in 2010.
"I think everyone realizes that we work good together," Hernandez said. "He will definitely be catching my starts this year. Oh yeah, he is going to be there."