BOSTON — Coming off a series sweep over the weekend against the St. Louis Cardinals — their first sweep of at least three games at home since 2023 — the Boston Red Sox were riding high as a four-game set against the Toronto Blue Jays began Monday.

But those good vibes took a turn in the first inning when catcher Connor Wong was hit on the hand by George Springer’s bat on a play that resulted in catcher’s interference. Wong remained in the game to finish the inning but soon exited.

After the game — a 6-2 loss that snapped the Red Sox’s five-game winning streak — manager Alex Cora said Wong had a fractured left pinky finger and will head to the 15-day injured list. There is no timetable for his return.

The Red Sox were already thin at the position after trading their top catching prospect Kyle Teel in a package for Garrett Crochet this winter. In Wong’s absence, Carlos Narváez will take on a majority of the reps behind the plate. Cora said the team had not decided which catcher to recall from Triple-A Worcester. Blake Sabol is on the 40-man roster and Seby Zavala is not. The Red Sox do, however, have an open 40-man spot after trading pitcher Quinn Priester earlier Monday. Zavala has more major-league catching experience and is known for his defense, and Sabol offers more offensive upside.

Regardless of whom they call up, the loss of Wong is a tough blow to a team that relied on him to catch more than 100 games each of the last two seasons.

“Obviously, frustrated,” Wong said. “I feel like that’s something we go over, who the potential catcher interference (batters) are. I knew that going in, felt like I was in a good spot and just bad luck, I think.”

Narváez, despite having just 11 big-league games to his name, has played well. Not only has he been solid defensively, he’s hit well, too, entering the day 6-for-14 (.429) before going 0-for-4 Monday coming off the bench to catch for Wong.

“Connor has been a very important piece for us, and he will continue to (be),” Narváez said. “I want to take (the opportunity) with accountability. Hopefully, Connor gets well soon. In the meantime, I’m going to take a lot of accountability to help the team win every game.”

It was 38 degrees at first pitch Monday, and the Red Sox kept the game close through six innings before it slipped away in the seventh after the Blue Jays scored two runs off reliever Greg Weissert.

Starter Richard Fitts battled for six innings through the rough weather, allowing three runs on six hits and four walks while striking out four. He threw 102 pitches, 67 for strikes.

“It was cold,” Fitts said. “I went out there in long sleeves and ended up sweating a little bit, so I took my long sleeves off, and, honestly, I felt pretty good, but more than anything, the wind made the ball a little bit slicker. I was licking my fingers every pitch. So trying to find anything to get grip on and doing what I can with that.”

A day after a 10th inning walk-off win followed by an 18-run outburst in their doubleheader sweep of St. Louis, the Red Sox offense was undoubtedly a bit tired, going 1-for-11 with runners in scoring position. The Red Sox managed just five hits Monday, their fewest in 11 games.

Nevertheless, thanks in part to a 13-run performance Friday and the 18 runs Sunday, the Red Sox finished Monday’s game hitting .271 as a team with a .781 OPS, ranking second and third, in the American League.

Alex Bregman, who won AL Player of the Week earlier in the day, added to his hot stretch, going 1-for-4 with a double. It was his fourth player of the week award. He hit .407 (11-for-27) with five doubles, two homers and 10 RBIs in six games last week. Bregman’s monster day Sunday in the second game (4-for-5 with two doubles and a homer) likely helped his cause.

Ceddanne Rafaela tried to set the tone for Monday’s game with a spectacular catch on the very first pitch of the game. Fitts gave up a deep fly ball to right-center and Rafaela raced toward the visitors’ bullpen, sticking out his glove before sliding into the wall on a catch that Statcast rated as having a 5 percent catch probability.

But Wong was injured four batters later, and it was downhill from there.