Toronto Blue Jays brass has wondered: When will Ricky Romero return to form? When will he become the pitcher that started back-to-back opening days for the Blue Jays, the one who showed so much promise?

Romero provided some answers on Sunday. The left-hander put together one of his best performances for the Buffalo Bisons, who rebounded from a sweep Saturday evening against Scranton/Wilkes-Barre with a convincing 7-1 victory in front of 8,525 at Coca-Cola Field. Romero, Toronto’s first-round draft choice in 2005, was the catalyst, throwing eight innings and allowing one run on four hits, four strikeouts and issuing one walk.

“The consistency of throwing strikes, being in the zone and getting a lot of quick outs, those were the results,” Romero said. “I let the defense work behind me, I had a lot of ground balls, a lot of pop outs and that how it’s been for the last month. I’ve been a lot better attacking the zone.”

It continued a positive trend Romero established on June 1 at Norfolk when his ERA hovered at 11.84. During his last eight starts since, he has lowered his ERA to 5.56. Romero (2-3) earned his first win of the season last Tuesday in a seven-inning gem over Syracuse in which he gave up two runs.

He has given the Herd (49-47) a quality start in four consecutive outings and six of his last seven games. In his last three starts, he has fanned 21 and walked just six in 27 innings.

“That’s as good as I’ve seen him,” Bisons manager Marty Brown said of Romero’s performance on Sunday. “He came out from inning one and really pounded the zone, didn’t hold anything back, got a lot of easy outs early in counts because he was pitching ahead for the most part. His secondary stuff was there, too, and he had command of it, so it was a very good day for Rick.”

Romero’s start to the season was troubling. After beginning the year in Class-A Dunedin and being recalled by Toronto on May 2 for a start against Seattle the next day, Romero didn’t last an inning in his next start against Tampa Bay. He allowed three runs and two walks on May 8 and was optioned to the Herd on May 10.

On May 11, Romero yielded six runs on 10 hits with no strikeouts in just 3∏ innings. Three starts later at Durham, he didn’t last an inning in an eight-run, eight-hit disaster. He clearly wasn’t the pitcher who went 14-9 in 2010 in Toronto and 15-11 with a 2.92 ERA a year later. The Blue Jays wanted the guy who opened their season in 2011 and ’12, not the one with velocity and mechanics problems.

“You get a little tentative and you start over thinking too much,” Romero said about his early-season woes. “Right now it’s that mentality of, ‘What do I have to lose?’ Go after the hitter and attack.”

Romero was certainly locked in and Brown didn’t see a reason to visit the mound Sunday. Why bother a pitcher whose fastball consistently clocked in the low 90s?

“You can see his confidence building, you see the fact that he believes and really sells out on everything he’s doing out there pitch-by-pitch,” Brown said. “It’s more now about the competition between his stuff and the hitter rather than before it was just not very confident, not knowing if he was going to throw strikes.”

Romero sat down the first five RailRiders before giving up a single to J.R. Murphy. Melky Mesa flew out to left to end the second inning.

Double plays in the third and fourth innings assisted Romero, and in the fifth he allowed a two-out single to Mesa before forcing a ground out by Thomas Neal.

Romero retired the side in order in the sixth but led off the seventh with a four-pitch walk to David Adams.

The old Ricky would have panicked, a precursor to an avalanche of runs. The more mature Ricky reached back and whistled a fastball by Randy Ruiz for a strikeout, then got Dan Johnson to ground out to second. Murphy’s double was harmless after Mesa flew out to right.

“You get into the mentality of attacking and not pulling back and start aiming,” Romero said. “It’s more, ‘Here you go, here’s my best stuff, hit it. If you hit it, so be it.’ ”

Said Brown on the inning-starting walk: “It didn’t affect him. … He figured out a way to make the adjustment on his own.”

Neal, Ibarra and Garcia went down in order in the eighth before Brown called on reliever Mickey Storey to get in some work before the All-Star break. Romero threw 92 pitches, 62 for strikes.

“Yeah, I had that mentality that I could have gone nine,” he said.

Romero’s prospects have turned around and another outing like Sunday’s could warrant discussions about a return to Toronto.

“Everyone understands Ricky is working his tail off down here and he’s getting back to where he needs to be,” Brown said. “Now it’s a timetable of what they’re looking at. I’ll give them a report that will be very positive. … With the stuff he had, he could compete.”