Most of that persona carries over to the game. For him, an emotional release may consist of nothing more than a confident stroll off the mound after a big inning.
But when his actions speak to the hitter, there's nothing soft about him.
There is a moment that Jimenez, without saying a word or making an overt gesture, sends the batter the message that his intentions are purely evil. It takes a trained eye, like that of Rockies manager Jim Tracy, to see and appreciate it.
"More times than not, it's after an out," Tracy said. "The infielders are throwing the ball around. He'll get the throw from the third baseman from the back of the mound. He likes to walk up to the rubber from the back of the mound.
"As he's standing there, he'll adjust his cap with his index finger and his thumb. The ball is sitting there in his right hand. Because of the size of his hand, the ball looks like a Pro V1 sitting there."
If Jimenez makes the baseball look like a golf ball before he throws it, it isn't that much more inviting a target after he unleashes it.
One of baseball's hardest throwers and one of pitching's brightest young stars, Jimenez is a reason the Rockies are on the verge of a playoff berth, and he could be a key to their chances of going far in the postseason.
Jimenez will go into Saturday's game against the Cardinals 8-2 with a 3.02 ERA since the All-Star break. Even more, Jimenez assumed a position of leadership this season. Veteran leader Aaron Cook missed five weeks with a sore right shoulder before returning for a successful start in Friday night's 2-1 victory over the Cardinals.
In Cook's absence, Jimenez established himself as one of the game's brightest young pitching stars and a leader by example for the Rockies.
Throughout the second half of this season, Tracy has not been shy about placing Jimenez in the upper-echelon of pitchers in the National League, even though he doesn't receive that type of acclaim nationally. Part of that has to do with Colorado's market size.
What's also an indication that Tracy might be correct is how Jimenez embraces such expectation. He demonstrated that last Sunday, when he struck out eight and held the D-backs to one run in seven innings of a 5-1 victory. It didn't matter that D-backs ace Dan Haren was opposing him.
"We beat a star in this league today," Tracy said after the game. "In order to do so, we had to hang right with them, and that goes back to our starting pitcher."
On Saturday, Tracy will give the ball to Jimenez again, then smile as he watches it disappear into the righty's formidable right hand.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.