Cubs ace Jake Arrieta addresses PED whispers during his historic run

Jake Arrieta's unparalleled turnaround has left many scratching their heads. The Chicago Cubs ace was a just a mediocre right-hander in 2013 with the Orioles, a club with which he spent his first 3 1/2 years in the majors.

Arrieta wasn't even a .500 pitcher in Baltimore, going 20-25 with a 5.46 ERA. He was sent to the Cubs in the middle of the 2013 season and his turnaround slowly took hold. He went 4-2 with a 3.66 ERA the rest of the way, but no one knew just how dramatic Arrieta's turnaround would eventually become.

Arrieta went on one of the greatest pitching runs in the second half of last season, going an absurd 16-1 — his only loss at the hands of Cole Hamels' no-hitter July 25 — to win the NL Cy Young. Arrieta even threw a no-hitter of his own Aug. 30 against the Dodgers.

Fast-forward to this season and Arrieta is staking claim as the best pitcher in the game. He's 4-0 with a 0.68 ERA and another no-hitter, last Thursday against the Reds. So of course when this type of turnaround occurs in baseball, whispers of PED use are soon to follow.

And Arrieta has heard it all.

"I've heard players, and I'm talking about some of the best players in the league,'' Arrieta told USA Today, "question whether I've taken steroids or not. Some of the things I hear are pretty funny, and some people are idiots, frankly.

"I'll see on Twitter, 'My close source revealed to me he's on steroids.' Well, the 10 tests I take a year say otherwise. I eat plants. I eat lean meat. I work out. And I do things the right way."

Many pointed to Arrieta changing his where he stood on the rubber, opting to throw from the third-base side, as a possible reason for his newfound success. The star righty credited Pilates for his turnaround in an interview earlier in the year.

But he's adamant that his success is a product of hard work and natural ability. Arrieta points to his velocity remaining constant throughout his career as further proof that his success isn't something artificial. 

"I threw 96, 98 (mph) when I was younger. And I still feel like I'll be able to do that for a long time," Arrieta told reporters. "If people call into question my work ethic, that's fine, because I know what I'm doing behind the scenes.

"It is somewhat flattering, especially when some of those comments are coming from some of the best players in the game."

Whatever the reason, big league hitters seem to be having all kinds of problems against the Cubs ace. And it doesn't look like that's going to change anytime soon.

The Associated Press contributed to this report.