By Matthew Geagan, CBS Boston

BOSTON (CBS) — The Patriots returned to game action Sunday following an impromptu two-week break filled with positive COVID tests, a sudden bye week and very little practice time. All of that showed in New England’s 18-12 loss to the Denver Broncos.

While many expected some level of rust, the Patriots’ complete inability to put much of anything together on offense was an extremely troubling sign from their third loss of the season. Most of the offensive issues can be traced back to an offensive line that is being held together by a shoelace and some gum. And that MacGyver-like patchwork was stretched to its limits throughout Sunday’s loss.

The Patriots entered the game without starting right guard Shaq Mason, who was placed on the COVID list Saturday evening. Starting center David Andrews missed his third game after undergoing hand surgery last month. Andrews’ fill-in, James Ferentz, landed on the COVID list on Friday.

All of that led to Cam Newton’s protectors playing musical chairs, with Justin Herron starting at left tackle, Isaiah Wynn moving from left tackle to left guard, Joe Thuney getting the start at center, and Michael Owenu and Jermaine Eluemunor on the right side. The lack of continuity along the New England offensive line was tested even further when Eluemunor was lost to an ankle injury in the first quarter, forcing Owenu to move to right tackle and Hjalte Froholdt to enter at right guard.

Newton didn’t really do himself any favors in his first game in two weeks, looking rather statuesque in the pocket for much of the game. Wynn did not have a good game in his new position, and the Denver defense feasted on the offensive line, sacking Newton four times while registering eight QB hits. That constant pressure — plus the inability for any of Newton’s targets to get open downfield — led to rushed throws by the quarterback. The Broncos picked Newton off twice, both of which were initially tipped off at the line.

The Patriots also got nothing on the ground, with running backs tallying just 41 yards on their 15 carries. Newton scrambled for 76 yards of his own, with 38 of those coming on a key fourth quarter run. But this was not the rushing machine we saw in three of New England’s first four games, when the Patriots racked up over 200 yards on the ground

When the Patriots can’t run the ball, the offense struggles to get into any kind of rhythm. Their inability to establish the run meant Newton never got comfortable in the pocket, and it left the offense with nowhere to go.

“Well it was a big challenge,” Bill Belichick said of the line’s play throughout Sunday’s loss. “Playing without guys, getting guys hurt, moving around, had some guys that haven’t played together much, hadn’t practiced together much. So we need to get on the field, we need to practice, we need to develop some continuity as a team, but especially there.”

“You know, it’s just football and kind of the next-man-up mentality. We’ve got a lot of trust in the guys, everyone in that room – the coaches, players,” said Thuney, who had a bad snap that led to a 15-yard loss in New England’s first trip into the red zone, leaving the Patriots to settle for a field goal. “It always comes down to execution, you’ve got to execute on Sundays. Regardless of positions, people, our whole room has that mentality of next man up and just got to execute better.”

The execution wasn’t there on many levels throughout Sunday’s loss, but the inefficiencies of the offensive line were front and center. Newton’s ability to improvise and pick up large chunks of yards somewhat masked the line’s issues over the first month of the season, but it caught up to the patchwork O-line on Sunday.

The good news is that Andrews, the linchpin in the line’s operation, is eligible to return this weekend against the San Francisco 49ers. His return will allow Thuney to slide back to left guard, and Wynn back to left tackle. And you’d hope that the team will get a few practices in this week, which would allow the line — either the real New England offensive line or the mish-mosh they had to use Sunday —  to build some level of comfort heading into Week 7.

But no matter which lineman the Patriots send out next Sunday, they have to be a whole lot better than they were against the Broncos. Otherwise, it will be another frustrating weekend for the entire offense.