But in the couple months they've been working together, they've had some passionate conversations.
"Joe is one that certainly has, I think, pretty strong opinions about some things," Caldwell said.
"We've talked them out, worked them out, and I think we can work together. That doesn't mean it's always going to be rosy, but I think for the most part it's going to be a real good, strong relationship."
Flacco was out the final two days of Ravens minicamp, and has not yet commented on his relationship with his new position coach.
But Caldwell says the two are getting along well.
"We're getting a feel for one another. We get along and those kinds of things. It's a great working relationship at this point," Caldwell told reporters Tuesday.
It's the fourth quarterbacks coach for Flacco in his five NFL seasons. Hue Jackson coached him in 2008 and 2009, Jim Zorn in 2010, Cam Cameron and Craig Ver Steeg last year and now Caldwell.
Caldwell said he's watched every game of Flacco's career, and he sees a very talented player. But he already knew that from his days coaching in Indianapolis.
What Caldwell has gained is more of an understanding of is Flacco's personality.
"He's highly motivated," Caldwell said. "He can be rather quiet, but Joe is very, very focused. He's working to improve everything in his game, from top to bottom. He's one of those guys who's never satisfied with where he is and he can always get better."
Flacco has looked very sharp thus far in organized team activities and one minicamp practice in a driving rain. Head Coach John Harbaugh and Offensive Coordinator Cam Cameron both raved about how well he has played, and that he looks to be improving daily.
Harbaugh said part of it is Caldwell's stress on the fundamentals. The coach often has the quarterbacks working on their footwork and getting rid of the ball quickly.
But there's a lot that goes into Flacco's development that has him in position to take another step in 2012.
Harbaugh noted that the organization has been building the offense around Flacco, putting players in place that fit his style.
"We're able to do some things with the offense that we think fit Joe," Harbaugh said, adding that if things come together, Flacco's career could take off.