Romero will now report to Triple-A Buffalo, where he'll continue working on his mechanics that were refined during Spring Training and the first month of the season.
"I think it's a combination of things, the performance, we need to get him to pitch, obviously get him to have some success, get some more innings under his belt," general manager Alex Anthopoulos said when asked for specific reasons behind the decision.
"We felt like we needed to give him more starts down there. I don't think it's as much about strike-throwing, even though there were still some walks, I think it's just about needing to go out there and pitch and have some success and string together some starts."
Toronto's decision to promote Romero from the Minors earlier this month has come under heavy criticism. Romero spent the month of April throwing bullpens and extended spring games in an effort to perfect his new mechanics.
The Blue Jays had Romero change his delivery with the goal of taking a more direct line to the plate. The other purpose was to have him not throw across his body as much, as he had in the past, and, by doing so, improve his overall command.
After Romero's work in extended spring was completed, he made just one start for Class A Dunedin before receiving a promotion. The club was in dire need of another starter after right-hander Josh Johnson was placed on the disabled list, and the accusation is that Toronto rushed Romero not because of his progress but because of circumstance.
That type of move could have the effect of reversing any type of progress Romero made with both the physical and mental aspects of his game, but was something Anthopoulos denied to a group of reporters Thursday evening.
"Hindsight is 20/20, I don't know, if we would have brought him up two weeks later, three weeks later, would this have occurred?" Anthopoulos said when directly asked if the club made a premature move. "You look at other players, we've had Travis Snider go down and I know he doesn't pitch, but we've had position players go down for months, come back and have to go back down again.
"Sometimes it takes time. Maybe it's one of those things, as confident as he felt and as much success he felt he was going to have ... maybe sometimes you end up failing a little bit here and he realizes he'll have to continue to work on some things. We have no question he's going to work hard and do everything he can, and he's a great competitor and he will be back."
Blue Jays pitching coach Pete Walker saw several encouraging signs from Romero's last outing despite the ugly pitching line. Romero surrendered four hits to the seven batters he faced but none of the balls were particularly well hit.
If some of the groundballs had been hit a different direction they likely could have been turned into double plays but instead got through holes around the infield for singles. Romero certainly didn't do himself any favors by issuing a pair of walks, but overall it wasn't quite as bad as the line might indicate.
But that's where the positives stop. Romero's velocity was slightly down and he appeared to be aiming the ball rather than just letting loose. Walker was asked whether a lot of the problems are mental and he didn't exactly deny it.
"That's hard for me to answer," Walker said. "But I think it's still a confidence issue in what he's done and getting back on a Major League field and competing like he did in the past. You know I think he had great intentions, but I still think there's a little hesitancy on his part and a little tentativeness. I think once he gets over the hump you're going to see the results going to be a lot better."
In a corresponding move, right-hander Edgar Gonzalez was designated for assignment by the Blue Jays on Thursday after allowing five runs in 4 2/3 innings versus Tampa Bay the night before. Right-handers Mickey Storey and Ramon Ortiz were promoted from Triple-A Buffalo to fill the two vacancies on the 25-man roster.