Romero, who entered last season as the lead man in the Blue Jays' rotation, struggled throughout 2011 and went from being the top gun in the rotation to pitching on the back end of a staff that now includes off-season acquisitions Mark Buehrle, Josh Johnson and R.A. Dickey.
Romero allowed three runs in three innings, including a long home run by Jhonny Peralta, in a 4-2 loss to the Detroit Tigers. Rick Porcello pitched five innings and allowed two earned runs for the Tigers.
After going 15-11 in 2011, Romero slumped to a 9-14 record with a 5.77 earned run average in 2012. He was the second-oldest pitcher in the Jays' rotation, and this year he is the second-youngest.
Romero said he has a new mindset this season and he isn't letting his latest setback bother him.
"I'll get better and I'll take the positive out of anything I did today," Romero said. "It's time to look at everything that is positive and not dwell on the negatives."
Romero said he is working on his confidence more than anything else.
"It's all about having confidence," Romero said. "I have talked with vets who say they always get their butts kicked in the spring, so I have a reason to be confident. I see a light at the end of the tunnel. I am working on things I need to work on and I'll be ready when it's time."
Blue Jays manager John Gibbons said he has total belief that Romero can regain his 2011 form.
"He just needs to find his balance," Gibbons said. "He is taking too much time on the mound. He'll find it."
Romero has a 7.27 ERA this spring, but said he isn't worried.
"I expect to be good when I get out there," Romero said. "If you look at it, it doesn't mean anything until the season starts. I'll be ready. I have my confidence."
Porcello, battling for the final spot in the Tigers' rotation, allowed two earned runs in five innings, including a home run to Andy LaRoche. Porcello is up against Drew Smyly for the last spot in the rotation and said he doesn't want to talk about trade rumours.
"Every time I go out there it gives me a chance to show what I can do," Porcello said. "Every time I go out to the mound I have to show what I can do. You are only as good as your last start."
Tigers manager Jim Leyland said he liked what he saw in Porcello and said he isn't close to making a decision on the fifth starter.
"You can tell he's been working on his breaking ball and he looks pretty good right now," Leyland said. "He looks really good."
Peralta lifted his spring training average to .194 with his second inning homer off of Romero. Austin Jackson hit a double and a triple to raise his average to .223.
NOTES: J.A. Happ will start for Toronto against Baltimore in Dunedin on Saturday. Jake Arrieta will go for the Orioles. ... Blues Jays RHP Sergio Santos will also make his return after a week off due to soreness in his right triceps muscle. ... Tigers LHP Casey Crosby was optioned to Triple-A Toledo and LHP Kenny Faulk was reassigned to minor league camp. Detroit ace Justin Verlander is scheduled to pitch against Washington Triple-A affiliate Syracuse on Saturday. ... Tigers RHP Shawn Hill will start Saturday against St. Louis.