"I've seen the back of his baseball card," said a smiling White Sox starter Mark Buehrle, who has worked with Cooper longer than any pitcher on the club's current staff.
To simply make it to the Majors is a rare accomplishment in itself, regardless of the results, and his time spent with the Twins, Blue Jays and Yankees is something of which Cooper is proud. But Cooper admits that he never felt at home as a player.
He never felt comfortable in his own skin. It's a vastly different feeling for Cooper as an employee in the White Sox organization since 1988 and at the big league level since July 22, 2002. In fact, Cooper might feel more at ease with the players as a coach than he ever did as a player.
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"Other teams have coaches who stay away, and the only time you see them is on the field," Buehrle said. "He'll come in the clubhouse and play cards, just like one of the guys. But our whole coaching staff is like that."
Since taking over as White Sox pitching coach, Cooper's pitching guidance has helped the White Sox to a 721-638 record with a 4.29 ERA overall. A more important number to look at would be the 704 quality starts put up under his watch since 2003, an average of 88 per season, the highest such Major League total during that time period.
Oftentimes people scoff at the quality start, with a pitcher only needing to allow three earned runs or fewer and complete just six innings. In the case of the White Sox, it represents the durability of the staff and Cooper's basic precept of his starting pitcher giving the team a chance to win every time.
Being one of the guys helps Cooper relate to the players and guide them to their goals, but it's no automatic translation to excellence. Then again, Cooper's big pitching theorem actually is not much deeper and fairly simple.
No, that's it exactly -- keep it simple.
"That's easy because I'm not smart enough to make it complicated," Cooper said with a laugh. "I guess the best answer is I'm just me. That's a wonderful thing in that I'm allowed to just be myself.
"Go out there and do what we do. I know what I believe in. Every coach learns more and more with time, trying to get better at the craft, and then I simply be myself and bring my personality to it."
Any individual familiar with the White Sox knows the phrase "Don Cooper can fix him" has been uttered more than a few times over the past decade when a talented but project-type hurler is brought into the fold by general manager Ken Williams. Cooper's overall positive results speak for themselves.
Take Gavin Floyd's arrival from Philadelphia, as an example. Floyd was the fourth selection in the 2001 First-Year Player Draft but had never lived up to his potential.
Employing the basic concept of throwing strikes and competing, Floyd became a 17-game winner in 2008 and has won in double-digits each of the last three years. Cooper pays close attention to video of pitchers, past and present, to make even minor adjustments in mechanics. But in the case of Floyd, it was as much mental as any sort of physical change.
"I forgot how to use my eyes to focus," Floyd explained. "Coop was the guy that freed me from all the stuff cluttered in my mind with mechanics. He was able to simplify everything and just have small goals and we built on them. I was able to find my natural ability over the course of time."
Then there's the case of Thornton, a first-round pick of Seattle in 1998 who simply was unable to harness his electric stuff within the strike zone for the Mariners. Coming to Chicago not only gave the hard-throwing southpaw a new big league opportunity, but with Cooper's assistance, Thornton became an All-Star setup man and is in line to become the team's 2011 closer.
Once again, the alterations made were rather basic.
"Aim low, miss low. If you miss, miss down and off. If you miss, don't miss in the heart of the plate," said Thornton of Cooper's pitching philosophy. "It's always quality pitches, executing pitches. His philosophy is something instilled in me in '06 and it has given me a lot of success in what I've done so far."
Cooper stands amazed at how pitching success at the Major League level comes down to the simplest ideas.
"You have to be adept at basic stuff," Cooper said. "For me, that's throwing strike one, getting ahead and being able to do it with all pitches to both sides of the plate.
"Mechanics are important, but you have to watch it. You can't over-coach. I don't think I'll ever be guilty of that because I don't coach much anyway. The stuff I focus on is the basics and mental stuff: what we are focusing on, and what's our goal?
"What are we shooting for?" Cooper said. "We are looking at each individual guy, and my goal every year is how do we get the best year out of this guy he has ever had in his life? That's the same every year, whether it's Buehrle or [Sergio] Santos. Buehrle has 10 years and Santos has 10 days in. That's the goal."
Santos came into camp last year as a converted infielder with just one year of pitching experience. Cooper immediately instilled confidence in the right-hander, whether he had a perfect outing or got roughed up a bit.
"They know I'm in their corner," Cooper said. "They should know that, and if they don't, they aren't really paying attention or watching. I care, and I want what they want."
Chris Sale arrived in Chicago, or more precisely in Baltimore, for his big league debut just two months after being at Florida Gulf Coast University. The left-hander explained how Cooper made the transition easy, reinforcing the point of not trying to be Superman and striking out every hitter he faced with the perfect pitch.
"Pitch your game and be confident in what you are doing and everything will be fine," said Sale of Cooper's advice. "He told me I obviously was there for a reason."
Having a little fun at Cooper's expense is not uncommon. Guillen refers to Cooper as the "guru," and when asked for a humorous moment from their working past together, three pitchers came up with a game at Dodger Stadium on June 26, 2008, when Cooper pulled his left hamstring after arguing a checked swing by Luis Mazza on a 1-2 pitch from Thornton.
That hamstring went when Cooper threw his clicker in disgust and missed a dugout step in the motion.
"One of the funniest things ever," Thornton said. "He still gets picked on a lot."
Of course, the jesting is done in good fun. The man who has found his calling as a coach remains one of the guys.
"Without a doubt he knows what we are all trying to achieve," White Sox pitcher John Danks said. "He's as competitive if not more so than us."
"Maybe my calling was to be a coach rather than a player," Cooper said. "When we won the World Series, I always dreamed as a kid I would be the guy catching the ball or hitting the ball or making the final pitch. I never dreamed I'd be the coach."
Scott Merkin is a reporter for MLB.com. Read his blog, Being Ozzie Guillen, and follow him on Twitter at @scottmerkin. This story was not subject to the approval of Major League Baseball or its clubs.