A closer look at those numbers reveals a pitcher who got sideways for a 12-game midseason stretch, when his off-speed stuff abandoned him and he went 1-8 with a 7.40 ERA and an opponents' batting line of .335/.378/.585.
That wasn't the same Smyly who started the season extremely well -- including eight scoreless innings of one-hit ball with 11 strikeouts at Fenway Park -- and finished it by going 5-1 with a 3.73 ERA and an opponents' line of .230/.281/.398 in his final 12 outings.
"It was a bit of a roller coaster," Smyly acknowledged last weekend, sitting in the dugout at Safeco Field during FanFest with his new team.
The culprit, he said, was the lost feel for his normally potent curveball, which left him too reliant on a low-90s fastball.
"I have to mix speeds," he said. "I'm constantly trying to get the hitter guessing. I know I can throw strikes. I know I'm not going to walk guys. But it's just commanding the ball inside the strike zone, throwing quality strikes and changing speeds and keeping the hitter off-balance, that's the biggest key to pitching."
Smyly's erratic season is no doubt one of the reasons the Rays viewed him as expendable, but Mariners general manager Jerry Dipoto sees a youngster just entering his prime who has already established himself on some outstanding Tigers teams and -- as a fly-ball pitcher -- should fit nicely in Safeco Field.
"He's a guy who throws strikes and has a history of missing bats," Dipoto said. "He's a pretty extreme fly-ball pitcher with low walks. With a greatly improved outfield defense in our park, he fits us like a glove."
Smyly's goal will be to keep more balls in his new park. He was sixth in the Majors in home runs allowed last year with 32.
"Obviously I had a little trouble with the home run ball last season, but hopefully this year a few of them don't go out and it makes a big difference on the whole season," he said. "Maybe Safeco Field will help a little bit. That can change a lot. One or two pitches can change the whole outcome of a game. I'll just go out and compete every five days and give it my best every time."
Smyly pitched on a World Series team with the Tigers as a rookie in 2012 and also was in the postseason the following year, so he brings a strong background to a Mariners squad looking for its first playoff appearance in 15 years.
"Learning from [Justin] Verlander, [Max] Scherzer, [Rick] Porcello, those are three Cy Youngs right there," Smyly said. "And Doug Fister. I was just the fifth starter in that rotation. It's crazy to think back. We had some really good teams and those guys taught me a lot.
"That was my first impression of professional baseball, and I learned a ton from those guys. How to show up at the field every day, how to be a pro, how to learn from the hitters, how to pitch. I'll carry that with me everywhere."
And new he's eager to learn from another Cy Young Award winner in new teammate Felix Hernandez.
"King Felix is a stud," he said. "I feel like I've been watching him since I was a kid, almost. It's incredible. I'm excited to meet him and learn from him and watch how he goes about his business. Maybe he can teach me a few things. This rotation is a lot of veteran guys, a lot of talent, so I'm excited to be a part of it and help out any way I can."