Rays manager Joe Maddon even went on record to suggest he would stack his lineup with as many lefties as possible to better combat Toronto's No. 1 starter.
Romero doesn't deny that his performance against those left-handers was an issue at times, and it's something he set out to improve.
"Not personally, but obviously the numbers don't lie, and it's something I want to get better at," Romero said when asked if he took offense to Maddon's comments in 2011. "I said every year, I feel like you have to get better at something, but that's one of the parts of my game where I want to continue to get better at -- getting lefties out."
Lefties hit .269 with a .372 on-base percentage against Romero compared to just .194 with an on-base mark of .263 for right-handers. It's a drastic difference in splits but Romero believes he has an idea of how to change his fortunes this year.
Romero entered Spring Training with the goal of refining his cut-fastball. The native of Los Angeles has more or less perfected the pitch to right-handed batters, but he has experienced difficulty using it against lefties.
"I haven't really got a chance to work on it in games yet, but in the bullpen, it has been getting better," said Romero, who pitched two scoreless innings against the Phillies on Tuesday afternoon in a 7-0 Blue Jays loss. "I've gotten a good feel for the cutter inside to a righty and now it's just front-dooring it to a lefty. It's going to come with time, and I'm going to continue to work hard on it."
Blue Jays manager John Farrell acknowledged an improved cutter to lefties could play a factor, but he also believes Romero's curveball will lead to better results as well.
"Any time you can create depth going away from a left-hander, that's the one that's going to slow some left-handers down," Farrell said. "They'll look out over the plate against him, know they'll probably get something hard away for the majority of the at-bat. But I think as he creates more consistency with the curveball against them, that's where he'll slow them down."