In other words, the 6-foot-5, 225-pound right-hander was the epitome of a workhorse. So when the No. 26 overall pick in the First-Year Player Draft began his career in the Milwaukee Brewers system and went a total of three innings over his first two outings, it was, well, different.
"It was definitely weird," Arnett, now a part of the Helena Brewers staff in the Rookie-level Pioneer League. "I usually don't get going until the third or fourth inning; I'm better in the middle innings. But I know it's only for this summer. It will be good in the long run, but it's a little difficult to get used to after starting."
Arnett made his debut on June 24, coming into the game in relief and pitching one inning. He gave up two runs on one hit and two walks, a combination of being a little amped up and a little rusty figuring into the performance. He had last faced live hitters in a game situation back on May 29, in the Hoosiers' Regional game against Louisville.
He followed that up five days later with the first "start" of his pro career. It lasted just two innings, but he was much sharper, allowing two hits and no walks or runs, striking out two.
"Once I got my feet wet, I've settled down a bit," Arnett said. "I don't think any pitcher wants to come out. I knew going into it, that I'd have limited innings each start."
This is a big departure from a guy who hit the 140-pitch mark in two different starts and was over 125 pitches on four other occasions. Those who are ready to cry abuse, something not uncommon in the college game, may want to wait. Arnett himself never really had a problem with it.
"I think pitch count is a little overblown," he said. "As long as you're not changing your mechanics, you're OK. I was throwing harder and better later in games. It never affected me.
"At the beginning of the year, we didn't have a really set bullpen or closer. You almost had to [go deep]. Every inning you can stay in was a good thing."
Arnett has a firm grasp of what he needs to do if he wants to continue to work as a starter. It's all about the secondary stuff for the right-hander, namely his splitter and his changeup. The latter is a pitch he knows how to throw, but never really did in college. He threw one change in that first outing -- out of the strike zone -- but that's been about it thus far. It might be something that will wait until instructional league after the Pioneer League season is over.
"People didn't need to tell me that. I know I'll need my changeup and splitter if I want to remain a starter," Arnett said. "Otherwise, I might have to move into relief. I definitely need to work on them."
Normally, when a pitcher goes to begin his career in a place like Helena, Mont. -- even a first-round pick -- he tends to fade into anonymity. The thousand or so fans who come to Kindrick Field on any given night might get to know a player like Arnett, but that would be about it. In today's electronic age, however, players don't have to disappear into the Minor League woodwork. Arnett has developed a pretty strong following on Twitter (he can be found @eric_arnett), something he started doing to let fans in on the Draft process, and something he has continued doing since he signed. It's been a good way for him to interact with fans, though he has learned that he shouldn't be the source of breaking news.
"I did get in a little trouble, so I'll have to watch what I say and when," said Arnett, referring to the fact he inadvertently broke the story of him signing with the Brewers. "I was surprised how many people were following me. I've got a bunch of Brewers fans on there. It's been fun, and I've enjoyed the support."
Jonathan Mayo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.