ST. PETERSBURG, Fla. -- Joey Butler waited a long time for the opportunity that came his way this season. And the Tampa Bay Rays waited a long time for what the 29-year-old rookie did Sunday at Tropicana Field.

Butler, the designated hitter, became the first Ray in over a year to hit a grand slam to power the Rays to a 12-3 thumping of the Toronto Blue Jays in each team's regular-season finale.

A 15th-round draft pick of the Texas Rangers in 2008, Butler appeared in 14 big-league games before hitting .276 in 87 games this year with the Rays. With the bases loaded and two out in the first inning Sunday, Butler crushed a Mark Buehrle pitch off the roof of the deep blue batter's eye in dead center field to the delight of most of the 15,815 in attendance.

Butler obliged the crowd by coming out for a curtain call.

It was Tampa Bay's first grand slam since Kevin Kiermaier hit one on July, 9, 2014, a stretch of 229 games. Butler's blast fueled a nine-run first inning, their biggest offensive explosion since they put 10 up on the then-Florida Marlins on June 25, 2008, and their largest rally at home since July 22, 2006 against the Baltimore Orioles.

"Scale of one to 10, probably a 12," said Butler, who added a two-run home run in the fifth to become the first Rays rookie since Evan Longoria (2008) to drive in six runs in a game.

"It was awesome, it was unbelievable. Just for this team, as hard as we worked to end the season with a victory was big."

Another rookie, center fielder Mikie Mahtook, also homered in the first inning for Tampa Bay, and went 2-for-5 with two hits, two runs scored and two RBIs. He hit .353 with six home runs and 13 RBI in 27 games since being recalled Sept. 1.

The Rays finished the year 80-82 and failed to make the playoffs in consecutive seasons for the first time since the Devil Rays days of 1997-2008.

"We realize there are things we need to improve on, first and foremost, myself," Kevin Cash said moments after wrapping up his first season as Rays manager. "There are plenty of things I can improve on, but a lot of positives (are) to be taken from this season. These guys do not need to be motivated. ... They hold themselves accountable, very accountable, and that's why we're so fortunate as a coaching staff."

Rays starter Matt Moore (3-4) allowed a run on four hits over six innings to earn the win. He underwent Tommy John surgery last July and was limited to 12 starts and went 3-4 with a 5.43 ERA.

"It makes my job easier having a 9-spot up there, but that's a tough lineup," said Moore, 2-1 over his last six starts. "It'll be exciting to watch them in the postseason."

Moore drew a peculiar counterpart in fellow lefty Buehrle, Friday's starter for Toronto who got the start Sunday because he needed two innings to reach 200 for the 15th straight season.

It did not go well. He needed 45 pitches to record two outs and allowed eight runs on five hits, though none of the runs were earned because of errors by first baseman Edwin Encarnacion and second baseman Ryan Goins.

"I couldn't just leave him out there to rot," Blue Jays manager John Gibbons said. "It's unfortunate, but that's the way baseball is sometimes. He's had a tremendous career, a tremendous three years here -- we're real proud of him."

Sunday's appearance was believed to be the last one of Buehrle's career. After the game, however, he said he had not come to a decision.

"This ain't the best way to go out, if this is it. But this ain't going to factor into it," said Buehrle, a winner of 214 games and a World Series title with the Chicago White Sox in 2005. "I'm going to go home, talk with my wife, Jamie, and then we're going to make a decision. It's probably going to be more my decision than hers, but she's going to listen to me and give her opinions."

Buehrle will not be on the roster when the Blue Jays open the American League Division Series at home Thursday against the Texas Rangers, who clinched the West Division title on Sunday.

"They made the right decision," Buehrle said. "We've got four guys who have been throwing the (stuff) out of the ball and they're going to take it and run with it. I'll be ready if something happens. Hopefully it doesn't, but if something happens to one of those guys in the second round or in the World Series, if we get to that point, I'll be ready."

Designated hitter Chris Colabello and second baseman Darwin Barney homered for the Blue Jays, off to the postseason for the first time since 1993 with their fifth-best record (93-69) in franchise history.

"It's been a tremendous year for these guys," Gibbons said.

NOTES: RHP Brad Boxberger led the American League with 41 saves, as he joined Rafael Soriano (45 in 2010) as the only Tampa Bay Rays to top the league in that category. ... Toronto Blue Jays RF Jose Bautista hit just .173 (9-for-52) against the Rays this season, but seven of those hits have been home runs. He walked in all three of his plate appearances Sunday. ... The Rays' 60 saves are most ever by a team with a losing record, but Tampa Bay's bullpen also led the majors in losses (37) and blown saves (27).