"Quit getting behind people," he said. "Attack 'em. Go at 'em."
Then Washington did something that caught Grimm by surprise. He reached up and tapped him on the cheek.
"He caught me off guard," Grimm said later. "It was like, 'Wake up.'"
Grimm got the message. He went back out and took control of the game, allowing just two baserunners over his final four innings before turning the game over to one of baseball's best bullpens in the seventh, and the Rangers defeated the Tigers, 7-2, in front of 46,782 at Rangers Ballpark.
He moved the ball around, kept hitters off balance and -- channeling his manager -- attacked the strike zone.
"I think [Washington] changed my mind-set," Grimm said. "He showed confidence in me. He's supporting me."
To understand the magic of these Texas Rangers, who have baseball's best record (28-15) and largest division lead (6 1/2 games), Grimm is a good place to start.
The Rangers have four starting pitchers on the disabled list. Their ace, Colby Lewis, is one of them. Their Opening Day starter, Matt Harrison, is another.
Yet the Rangers have the American League's best ERA, at 3.38. In a season that began with all sorts of uncertainty, it has become an affirmation of the depth and quality of the organization that general manager Jon Daniels has assembled.
"What I'm most pleased about is the accountability they have with each other and bring to the ballpark every day," Washington said. "They come to play baseball. They don't get involved in what's happening, drama, all that type of stuff. They're about just playing baseball. That's the thing I love more than anything else. They love to play the game. They come every day, and they leave their hearts on the field. They never let one day go into the next, and that's what's most powerful about them."
Few people were picking the Rangers to finish in front of the A's and Angels in the AL West after an offseason in which they traded their clubhouse leader, Michael Young, and lost Josh Hamilton, Mike Napoli and two key relievers, Mike Adams and Koji Uehara.
Daniels shored up his roster by signing two respected veterans, Lance Berkman and A.J. Pierzynski, to one-year contracts. The two fit nicely into a lineup built around the best left side of the infield -- third baseman Adrian Beltre and shortstop Elvis Andrus -- in the Majors.
Rather than fret about the offensive firepower they'd lost in Hamilton, they feel good about the players who cover his at-bats. First baseman Mitch Moreland homered for the seventh time in 13 games on Saturday and is taking advantage of increased playing time. The platoon of Craig Gentry and Leonys Martin has played a Gold Glove-caliber center field and produced five triples and three home runs.
Still, the Rangers are just sixth in the AL in runs. But even with the four starters hurt, the strength of the team is a homegrown staff. Not one of their six starting pitchers has thrown a game for another Major League team. That's also true of their three most frequently used relievers.
Washington got 6 2/3 innings from Grimm against the Tigers, then ran out two products of the farm system for four outs before handing the ball to closer Joe Nathan in the ninth.
The Rangers are 8-7 in games started by their replacement starters, Nick Tepesch and Grimm, and have blazing fastballers -- most notably Robbie Ross and Tanner Scheppers -- to cover the innings between the starters and Nathan.
With Yu Darvish putting up potential Cy Young numbers and Derek Holland establishing himself as an elite starter, it's hard not to project these Rangers into October.
Whoa, they say.
"It's a little early to say that," Berkman said, "but we've got the makings of a championship-caliber ballclub. All the elements are in place. It's just a matter of [whether we can] continue to execute at the same level we've been executing."
The Rangers surely wondered how the clubhouse would evolve in the wake of Young's departure. Beltre has been tremendous. Andrus, who had five hits on Saturday night, is a talkative, energetic presence.
And Berkman and Pierzynski had been around the block a few times before joining the Rangers.
"The team we have here, I think we're pretty special," Moreland said. "We've got a great group of guys. It seems we find ways to win. We can do it in so many different ways. We've got a lot of guys who step up."
Richard Justice is a columnist for MLB.com. Read his blog, Justice4U.