SAN DIEGO -- Shortly after the Boston Red Sox defeated the San Diego Padres 7-2 on Wednesday night in the rubber match of a three-game series at Petco Park, the big picture came into focus.

Wednesday night's win, coupled with Toronto's loss to the Yankees in New York, had moved Boston back into a one-game lead in the American League East going into a three-game series against the Blue Jays starting Friday in Toronto.

Then the Red Sox return to Fenway Park on Monday for a seven-game homestand against the Orioles, who are two games out.

With Thursday being an off day, Boston manager John Farrell has tweaked his rotation for the upcoming showdowns.

Right-hander Rick Porcello and left-hander Eduardo Rodriguez will start the first two games in Toronto with Clay Buchholz starting Sunday.

David Price, who won Wednesday night's game in San Diego with model efficiency, will start Monday's opener of the Baltimore series at Fenway Park with Drew Pomeranz being pushed back from Sunday to Tuesday.

"Our rotation, with Clay being put in Sunday, seems like one guy passing it off to the next guy," Farrell said Wednesday night.

"David Price was extremely efficient tonight with the number of pitches he threw. I think that was his best strike ratio of the sesason. He kept it under control and kept throwing strikes."

Price threw 98 pitches in seven innings. Seventy-six went for strikes as he allowed six hits and no walks with eight strikeouts.

Price extended his streak to wins in six straight starts to improve to 15-8.

"I definitely felt good tonight to keep the ball away from the middle of the plate and execute pitches," Price said.

After Price worked his magic, the Red Sox got another boost when right-handed reliever reliever Koji Uehara pitched a scoreless eighth in his first outing since July 19. He had been on the disabled list with a right pectoral strain.

Offensively, Travis Shaw and Dustin Pedroia combined for five RBIs and Hanley Ramirez and pinch-hitter Brock Holt hit late solo homers.

Shaw drove in Boston's first three runs, including a two-run homer off Padres starter and loser Jarred Cosart (0-3). Pedroia capped a three-run Boston third with a two-run double off reliever Carlos Villanueva after Cosart was forced to leave the game with the double whammy strains to his right hamstring and groin.

The game see-sawed into a 2-2 tie after three innings before an errant toss by Padres first baseman Will Myers resulted in the departure of Cosart and triggered a three-run Boston fourth.

With one out in the fourth, Jackie Bradley Jr. hit a hopper toward first that Myers charged and made an under-handed flip to Cosart, who had to look back toward Myers while trying to find the first-base bag.

Cosart caught the ball but missed the bag and landed awkwardly on his right leg. Cosart immediately departed the game with the double strains.

"I felt like I hyperextended on my way up as I was trying to find the bag, then landed awkwardly on the way down. It grabbed me pretty good. It was a fluke deal.

"For the most part, I felt pretty good. I was holding my own against one of the best pitchers in baseball. The rest is kind of history."

Padres manager Andy Green said, "We're not sure how severe the injuries are. At first, we thought it might be a cramp, but we didn't want to let him try again."

Villanueva replaced Cosart and immediately gave up back-to-back singles by Chris Young and Shaw, the second hit scoring Bradley with the tiebreaking run. After Price struck out and Young and Shaw both advanced on a double steal, Pedroia hit a two-run double to make it 5-2.

Cosart allowed three runs (two earned on Shaw's homer), two hits and two walks in 3 1/3 innings.

The Padres took a 1-0 lead in the bottom of the first against Price on a two-out single by Myers, who scored from first on Yangervis Solarte's perfectly-placed double. Solarte hit a sharp grounder inside the third-base bag that rolled all the way into the left field corner.

Cosart walked Bradley with one out in the third, then gave up a 425-foot, two-out rocket into the right-field stands on the first pitch to Shaw, who started at third base Wednesday after prized rookie Yoan Moncada struck out seven times in seven at-bats in the first two games of the series.

The Padres tied the score in the bottom of the third. Cosart opened the inning with a single and advanced to second on a single by Jon Jay, who was starting his first game since suffered a right forearm fracture when hit by a pitch back on June 19.

Luis Sardinas bunted the runners to second and third and Cosart scored on a sacrifice fly by Myers.

Hanley Ramirez widened the Red Sox lead to 6-2 when he opened the eighth inning by hitting his 21st homer on the first Major League pitch thrown by Padres' right-hander Jake Smith. Smith, 26, a 48th-round draft pick of the Giants in the 2011 draft, was promoted by the Padres from Double-A San Antonio earlier Wednesday.

NOTES - The Padres paid tribute to retiring Boston slugger David Ortiz before Wednesday's game, although the Red Sox designated hitter was limited to pinch-hitting duties during the three games at Petco Park. ... Thanks to Thursday's off day before the Friday night's opener of the Blue Jays series in Toronto, the Red Sox are altering their rotation. RHP Rick Porcello and LHP Eduardo Rodriguez will start the first two games in Toronto with Clay Buchholz starting Sunday. David Price will start Monday's opener of the Baltimore series at Fenway Park with Drew Pomeranz being pushed back from Sunday to Tuesday.