"I think I can mix it up a little bit better," Hellickson said before Wednesday night's game against the Blue Jays at Rogers Centre.
The 25-year-old will make his third career start against the Blue Jays on Thursday. He is 1-0 with a 4.26 ERA against them.
He allowed five runs on three home runs in five innings to the Red Sox in a no-decision on Saturday, a 13-5 loss for the Rays.
"I felt like I threw well in the last game, there was just that one pitch in the fifth that cost me," Hellickson said, referring to a two-run homer by David Ortiz that tied the game.
The five runs matched Hellickson's career high. He allowed five runs against the Orioles last June 10 at Baltimore.
"I've got to mix it up a little better, throw more strikes," he said. "I've just go attack better. We're going after guys but just missing. You don't want to leave balls too much over the plate. At the same time you want to be around the zone and make the pitches you want."
Hellickson also felt he got away from using his changeup early in the game.
"It wasn't there and I went away from it a way too early, I think," he said. "The changeup is obviously one of my better pitches and I need to throw that a little bit more than I did last game. I threw a lot more cutters too. I felt like I threw what I wanted to throw, but I didn't execute."