I heard it best explain, that the Orioles had poor pitching coaching, more worried about TTP and rubber location. At the same time, Jake was hard headed and not coachable.
So might be some truth to both sides, and being traded was a wake up call, and a good coach that fixed his issues.
There is such a fine line between excelling and sucking with these guys.
The O's had three pitching coaches during Arrieta's four years in Baltimore, but it was their organization-wide edict against throwing the cut slider that really set Arrieta behind the 8 ball.
“Why don’t you take a look at the chart with the average against cutters in the big leagues, batting average against and then come back and tell me that that’s a great pitch,” Duquette said. In an interview with Steve Melewski that is destined to provide content for weeks, Dan Duquette outlined the Orioles’ philosophy when it comes to the cut fastball. In essence, the pitch won’t be taught in their minor league organization. “We don’t like it as a pitch,” the Baltimore GM said.
The Time to the Plate nonsense that Buck Showalter conflated with success on the diamond also messed him up as well.
You can call Arrieta stubborn. Most pitchers are. But they tried to reinvent Arrieta in the big leagues to fit their organizational policies, despite the successes he had in the minor leagues.
The Cubs didn't exactly reinvent the wheel when the fixed Arrieta. They simply told him to throw the pitches he wants to throw, and yeah, change up his arm angles and positions on the rubber.