"There are still a whole bunch of things that I can work on," Harden said. "Getting experience and really learning how to pitch, I think I can get to a level of consistency where I am throwing a lot of strikes. I can cut down on my walks as well.
"Also, I think that there is a large part to the mental side of the game such as thinking about how to pitch to certain hitters and how I can move my ball around and still hit my spots. That is very important."
Harden's extra work during the All-Star break seemed to pay off. He was 6-2 over 10 starts in July and August before suffering a strained lat muscle on Aug. 19.
The hard-throwing right-hander was limited to just five innings over four relief appearances after the injury. The injury was among the more serious blows to then-surging Oakland's attempt to catch the Angels for the American League West title.
The A's ultimately fell short and Harden had to deal with a solid, but unfulfilled season. He finished with a 10-5 record and a 2.53 ERA.
Harden didn't qualify for the league leaders because he pitched just 128 innings. Nonetheless, among AL pitchers with 100 innings pitched, he had the lowest opponents' batting average (.201) and allowed the fewest home runs per nine innings (0.49). Only Roy Halladay had a better ERA.
While Harden and the A's fell short of their goals in 2005, they are well positioned for the future. Harden is part of a staff that features veterans Barry Zito and Esteban Loaiza and fellow youngsters Danny Haren and Joe Blanton.
It isn't hard to envision Oakland heading back to postseason play sooner rather than later. A healthy Harden would likely hasten that trip.
"He is huge for us," reliever Justin Duchscherer said. "He is only 24 years old and he has one of the best arms I have ever seen, and I have been playing for almost 10 years. If he puts it all together, with his command and his stuff, he is going to be one of the best pitchers in this game for a long time."
A 17th-round draft choice in 2000, Harden has only been a professional pitcher since 2001, and 2005 was just his second full season with Oakland.
That's part of the reason why the education process continues for Harden. His improvement has been fast and steady.
"I've learned to pace myself better out there," Harden said. "I used to go out and just try and throw it as hard as I can. Now, when I pace myself, by the end of the game, there isn't much drop off. At the beginning of a game, if I use 80-percent effort, I can still get a decent amount of velocity. Then I slowly build up as the game goes along, yet I still maintain my velocity."
It's scary for opponents to consider that Harden hasn't reached his peak as a pitcher. But it's true.
"He has a terrific arm and an easy motion. He also has a great fastball and hard slider to go along with great composure," said ESPN analyst Dave Campbell.
The fastball can reach 97 mph and he combines it with a hard slider, a solid changeup and a split-finger. He also has good command for a power pitcher. He had 121 strikeouts and 43 walks over his 128 innings in 2005 while posting a 1.06 WHIP.
"Obviously my fastball is something I use to set up my other pitches. When I control that, everything else comes off of that," Harden said. "I throw my changeup, which I've worked on the last couples of years, and my split-fingered fastball and my slider."
It would probably be a mistake to think that Harden's performance won't improve some more in 2006.