For the Red Sox, who clinched the American League East in New York on Wednesday night, there's the matter of home field advantage in the playoffs.
The series is not as critical for the Red Sox as it is for the Blue Jays, but playing extra home games at Fenway Park, where Boston is 46-32 this season, would be a bonus they can still earn.
Toronto dropped two of three to the Baltimore Orioles in Canada, putting the teams in a flat-footed tie for the two wild card spots. Detroit is 1 1/2 games behind while Seattle is two back.
"Boston is a tough place to play but our guys play pretty good there," Blue Jays manager John Gibbons said after Thursday night's loss. "I'm not worried about our guys. We've got our backs up against the wall but we're a good spot. It won't be easy, it's not supposed to be easy up here."
Said Toronto right-hander Marcus Stroman, who took the loss Thursday: "The team mentality has never changed, not once. We're fine. We're fine."
The Red Sox, swept in the three-game series in New York, will honor Ortiz on Friday night and Sunday. They have a magic number of one for elimination (behind Texas) for the top spot in the AL, but come in a half-game ahead of the Cleveland Indians for what would be home-field advantage in that matchup.
Boston owns the tiebreaker with Cleveland but does not with Texas.
"It's important. I think anyone who looks at home field advantage, it's pivotal," Red Sox manager John Farrell said. "It's something that we're continuing to strive for but we needed to give some guys a day off their feet given what we've come through, particularly the number of road games that we've played over the past six weeks. We go back home. We're looking forward to finishing out against Toronto."
Farrell rested several of his starters and removed Ortiz after two at-bats following the pregame Yankee Stadium ceremony in his honor. He will likely play his guys Friday night and see what happens from there.
"We know that there's going to be three days off next week in which to recharge some," Farrell said before Thursday night's game. "Still the importance of winning and maintaining our daily approach is priority number one.
"How that might affect how deep a starter goes in the upcoming games might be looked at a little more close but still we feel it's imperative to at least secure as much home field advantage as we can."
Porcello comes into the game with a 22-4 record and a serious candidate for the Cy Young Award. He is 3-0 against the Blue Jays this season, but 7-7 with a 5.07 career ERA against the Jays.
Two of their sluggers have hit him as Jose Bautista is 15-for-36 with three home runs and Edwin Encarnacion 13-for-37 with three homers. But Michael Saunders is 1-for-16, Melvin Upton Jr. 1-for-9, Troy Tulowitzki 3-for-15 and Russell Martin 3-for-20.
Estrada (9-9), who has allowed only one earned run in 14 innings in his last two starts, is 2-2 against the Red Sox this season and 4-4 with a 4.15 ERA in his career.
He has done a good job against some big Boston guns with Xander Bogaerts going 2-for-19, David Ortiz 3-for-19 (two homers) and Mookie Betts 2-for-13 against him. Dustin Pedroia is 7-for-19 and Hanley Ramirez 5-for-16.