Portland Sea Dogs pitcher Bryan Mata has had a rough August, but on Wednesday he struck out eight and walked none in four impressive innings against Reading before heavy rain forced the game to be canceled. Shawn Patrick Ouellette/Staff Photographer

August had been a rough month for one of the top Boston Red Sox pitching prospects, Bryan Mata, who earned a promotion to the Double-A Portland Sea Dogs earlier this summer at age 20.

In one start, he failed to record an out. In his three outings, opponents had batted a robust .395 with a slugging percentage of .698.

On Wednesday afternoon against division-leading Reading, none of those numbers changed, but Mata’s stock soared. He struck out eight and walked none in four impressive innings before heavy rain delayed matters, ending his outing at Hadlock Field.

After a two-and-a-half-hour delay, the teams tried to play one more inning to make it a legal game, but action lasted only two batters in the top of the fifth before the skies opened again. Half an hour later, the game was officially canceled and will not be made up, erasing all statistics from a contest Reading led 1-0.

Even so, Mata’s turnaround did not go unnoticed.

“He definitely felt more confident and comfortable on the rubber today,” said Sea Dogs Manager Joe Oliver. “It was refreshing to see after his past couple of starts where he just hadn’t been as (sharp).”

Mata struck out the side in the first inning on 13 pitches, showing a fastball that touched 96 mph.

He caught two batters looking and got through the second inning on only nine pitches.

Following a lead-off single in the third, he induced a double play and caught another batter looking at a 78-mph curve.

In the fourth, Mata fanned two more to raise his strikeout total to eight, matching his season high. Reading managed to scratch out a run with an infield single, a stolen base and a fisted blooper into shallow right field on a tough two-strike pitch to the Phillies’ top minor-league prospect, Alec Bohm.

The young right-hander from Venezuela needed only 54 pitches (34 strikes) and faced one batter over the minimum. Each of the three times he reached a three-ball count, he came back for a strikeout.

“By far, the best,” Sea Dogs pitching coach Paul Abbott said of Mata’s start, his 10th since his July 1 promotion to Double A.

Mata’s numbers in July weren’t bad. Opponents hit .270 and slugged .365 in his six starts. He went 2-3 with a 4.11 earned runs average, but August’s struggles inflated those numbers to 2-6 and 6.20.

He seemed to turn a corner in his previous start, losing 4-2 at New Hampshire after yielding four hits in six innings. He struck out seven and walked two.

Wednesday showed continued improvement.

“I came in with a lot of confidence,” Mata said in Spanish through interpreter Dedgar Jimenez. “I made pitches with more conviction and more movement. My fastball had more life.”

Abbott said Mata made an adjustment before his New Hampshire start by raising his arm slot, allowing for more consistency from his three-quarter delivery.

“That gave him better direction, and more depth to his breaking balls,” Abbott said. “He’s 20, so there’s always going to be some wrinkles that need to be ironed out.”

Mata’s poise through his rough patch did not go unnoticed.

“He’s a pretty mature 20-year-old,” Abbott said. “He doesn’t let the game speed up on him.”

While not as dominant at Mata, Reading starter Colton Eastman proved more effective. Eastman gave up lead-off singles in three of the first four innings but kept the Sea Dogs off the scoreboard.

With the bases loaded and one out in the third, Portland cleanup hitter Joey Curletta battled from from an 0-2 hole by fouling off seven pitches before Eastman finally got him to chase a 2-2 curve. A foul pop off the bat of Luke Tendler on a 3-1 pitch stranded the runners.

NOTES: The Sea Dogs activated infielder Josh Tobias from the injured list, assigned infielder Michael Osinski to High-A Salem and received right-handed pitcher Anyelo Gomez from Salem. … Because there was no official game, there is no official attendance. … Fireworks are scheduled after the conclusion of Thursday night’s game, the first of four scheduled against the visiting Trenton Thunder.