Romero, who entered the season as Toronto's ace, was tagged for a season-high eight earned runs, walked six, and needed 90 pitches to get through three innings -- his shortest outing of the season.
Manager John Farrell thinks that Romero's struggles can be corrected by slowing down the game and locating his fastball with more consistency.
"The thing we are continuing to emphasise with him is the importance of strikes with his fastball to his arm side," Farrell said. "When he has executed that pitch, that's when he has been able to make some right-handers reach over the outside part of the plate. ... The basic principles apply here, and that's getting strike one, or in some cases, when you have to get back in a count, have an area of the plate where you can go to to get that strike.
"For any left-hander, that's a pitch [where] when executed, they have a chance to be big winners."
So far that has been the case with Romero, despite his 4.94 ERA and 1.43 WHIP. The lefty has an 8-2 record, one year after winning a career-high 15 games in 2011.
Farrell thinks Romero did a great job last season of attacking his arm side of the plate and routinely getting strikes. That helped Romero post a sparkling 2.92 ERA and become one of the top left-handers in the game.
"He's trying, I know that," Farrell said. "I think at times, when thoughts get in the way of a delivery, you are going to have some inconsistencies to execute that. That's when the misfires start to come in."
Farrell says it's something that every player goes through. The mental component of the game, he says, is very real, and he believes it is only human nature that it could affect a player's performance from time to time.
"It has to be back to executing one pitch at a time."
Romero will look to get back on track in his next start, on Monday against the Royals, whom he dominated back in April.