Last year the Red Sox were able to hold it together for a while. The club remained competitive in the Wild Card hunt into mid-August, but a stretch of 16 straight days without an off day, which ended with 10 straight games against the Houston Astros and Los Angeles Dodgers, proved too much to overcome.

If this year’s Red Sox don’t ultimately make the playoffs, we may look back at this weekend as the moment the club reached a similar breaking point.

With Sunday’s 10-2 loss to the Astros, the Red Sox were swept for the first time since the Dodgers series in mid-July and for only the fourth time all season. The club has now lost four straight games to tie its longest losing streak of the season, and Boston (61-55) will go into Monday trailing the Kansas City Royals by three games in the American League Wild Card race.

None of that is good, but what’s worse is the possibility this club may have just sustained a blow from which it can’t recover.

On Friday morning the Red Sox lost Cooper Criswell for the week due to a positive COVID-19 test. He was scheduled to start Saturday in place of Nick Pivetta, who was scratched due to arm fatigue, and instead the Red Sox had to burn all of their long-relief options to make it through the day.

Then on Sunday, the Red Sox needed James Paxton to pitch as deep as he possibly could. Instead the veteran left-hander could only get two outs on five pitches before leaving with a right calf strain, leaving an already depleted Red Sox bullpen to figure out a way to get 25 outs.

In the short term the Red Sox bullpen will be running on fumes heading into this week’s upcoming Texas Rangers series. In the long term Paxton’s potential absence will add even more stress to a rotation that has already begun showing major signs of strain.

On top of that, the red hot offense that has kept the club afloat over the past few weeks finally seems to be cooling down.

Sunday was about as deflating a day at the ballpark as the Red Sox have experienced all season. After Paxton left with his injury the bullpen managed to keep things competitive through four innings, limiting Houston to a run in the third on a Brennan Bernardino wild pitch. But then things came unglued in the fifth, when the Astros scored five runs on back-to-back home runs by Alex Bregman and Yordan Alvarez and an RBI single by Jake Meyers.

Bregman’s was a three-run shot that cleared the Green Monster following two quick singles to lead off the inning, and Alvarez’s solo shot was a bomb to dead center that felt in the moment like a dagger. But just to be safe Houston piled on four more runs in the sixth, getting a two-run double from Yainer Diaz and a two-run home run from Jeremy Peña.

Meanwhile, the offense could barely manage anything off Houston starter Hunter Brown until the sixth inning, when Brown ran out of gas, loaded the bases and walked in a run to end his outing. He was charged with two runs over 5.1 innings with nine strikeouts after Masataka Yoshida tallied an RBI single off reliever Caleb Ferguson, but Connor Wong grounded into a double play with the bases still loaded to end the threat.

The two runs scored was the fewest in a game by the Red Sox since July 28.

The only real highlight for the home team was first baseman Dom Smith’s scoreless ninth inning on the mound. Smith threw mostly junk, including a 32 mph eephus pitch, but was able to keep the Astros off the board. It was his third scoreless inning in as many garbage-time appearances this season, and he received a standing ovation from the crowd as he walked off.

But at the end of the day, Sunday was a low point for the Red Sox. The question now is whether it’ll prove to be a bump in the road or the beginning of the end.

Last year the Red Sox didn’t have the pitching to carry the club through to the end, with things famously coming to a head against the Astros at Fenway on Aug. 28. That’s the night Triple-A call-up Kyle Barraclough was thrown to the wolves for 10 runs allowed over 4.2 innings because the Red Sox had nobody left available in the bullpen.

This year’s Red Sox should theoretically have more depth to draw from. The club could promote 23-year-old right-hander Quinn Priester, who was also acquired at the trade deadline and has 14 MLB starts under his belt, and the Red Sox were also in attendance for 44-year-old veteran Rich Hill’s recent showcase.

But at the end of the day, those guys, Paxton, Criswell and whoever else the Red Sox slot into the No. 5 position will only matter if the club’s four main starters can pull their weight. Since the All-Star break Tanner Houck, Kutter Crawford, Brayan Bello and Pivetta have combined to post a 6.35 ERA over 83.2 innings, which obviously isn’t good enough.

Bello will be counted on to pick the team up Monday when he’s activated from the paternity leave list to start the opener against Texas. A big outing could help reset the bullpen and get the Red Sox back on track, while another dud could send the club snowballing even faster down the standings.

One way or another, the next week could go a long way towards determining what kind of season this is ultimately going to be.