Following that forgettable performance, Howell made a vow to himself.
"I just said, 'OK, man. I'm just going to go back to the basics and keep it simple,'" Howell said. "It's a lot more easy to concentrate and focus on one thing rather than 105 things."
The left-hander hasn't allowed a run since, throwing 4 1/3 scoreless innings and giving up just two hits.
It wasn't easy to get to this point, though. Howell, who missed a year due to shoulder surgery, didn't look like himself on the mound upon his return on May 20. In his first five appearances, he allowed seven earned runs in 3 1/3 innings.
"When you first come back, it's choppy," Howell said. "You don't ever feel comfortable and you never trust your stuff. When you start getting out there and you get beat up a little bit, you start wondering why.
"It was real frustrating. You start fighting negative thoughts, and once you go there, it's tough to get out of it. It's a constant battle to stay positive."
In Howell's latest outing on Friday against the Marlins, manager Joe Maddon was surprised to see an 89-mph pitch from his left-hander, who usually keeps his velocity in the mid-80s.
"I went out to the mound and said, 'Dude, there was an 89 in there,'" Maddon said. "He looks really good. He's going to get sharper, his confidence is going to build. But I just like the idea that he's healthy, and if he is throwing 87 and 89, that really indicates shoulder health to me."