The Red Sox are under .500 for the first time since June 30 after losing to the Blue Jays 4-3 in 13 innings on Saturday.
Toronto has a chance to sweep the series when the teams face off this afternoon at the Rogers Centre.
The Red Sox have lost three in a row and 14 of their past 20 games. With 13 games to play, Boston is eight games back from a wild-card berth. Toronto currently holds the third and final AL wild-card slot.
Nick Pivetta will be on the mound for Boston; Toronto will counter with Hyun Jin Ryu.
On Monday, the Red Sox head to Texas for a three-game series against the Rangers before returning home to face the White Sox and Rays.
RED SOX (74-75): Rafaela CF, Refsnyder LF, Turner DH, Devers 3B, Duvall RF, Reyes 2B, Story SS, Dalbec 1B, McGuire C
Pitching: RHP Nick Pivetta (9-9, 4.56 ERA)
BLUE JAYS (82-67): Springer DH, Bichette SS, Guerrero Jr. 1B, Schneider 2B, Biggio RF, Chapman 3B, Kiermaier CF, Varsho LF, Heineman C
Pitching: LHP Hyun Jin Ryu (3-3, 2.93 ERA)
Time: 1:37 p.m.
TV, radio: NESN, WEEI-FM 93.7
Red Sox vs. Ryu: Bobby Dalbec 3-7, Rafael Devers 3-9, Adam Duvall 5-12, Reese McGuire 0-1, Rob Refsnyder 0-1, Pablo Reyes 0-1, Trevor Story 4-17, Justin Turner 1-3, Alex Verdugo 3-5, Connor Wong 0-1
Blue Jays vs. Pivetta: Bo Bichette 10-28, Cavan Biggio 5-14, Matt Chapman 4-22, Santiago Espinal 3-12, Vladimir Guerrero Jr. 6-28, Tyler Heineman 0-1, Kevin Kiermaier 4-15, Alejandro Kirk 4-12, Whit Merrifield 3-12, Davis Schneider 1-1, George Springer 10-24, Daulton Varsho 3-6
Stat of the day: Toronto was 3-for-16 with runners in scoring position and stranded 13 runners on Saturday but still won.
Notes: Toronto is scheduled to start left-hander Hyun Jin Ryu (3-3, 2.93 ERA) on Sunday. In six career starts against Boston, Hyun Jin Ryu is 2-2 with a 4.01 ERA. ... Right-hander Nick Pivetta (9-9, 4.56) is Boston’s scheduled starter in the series finale. He is 2-4 with a 5.57 ERA in 14 career games (12 starts) against Toronto. ... Boston put first baseman Triston Casas (right shoulder inflammation) on the injured list Saturday and recalled infielder Bobby Dalbec from Triple-A Worcester.