A week ago, Georgia Tech presented a best-case scenario of what it could accomplish without forward Robert Carter, who likely is out for the season with a knee injury.

The Yellow Jackets’ past two games, though, have offered a glimpse at the other end of the spectrum, the latter demonstration a gear-grinding breakdown Saturday afternoon at McCamish Pavilion. The Jackets lurched through one of the poorest performances in coach Brian Gregory’s three seasons in a 56-42 loss to Miami.

“Disappointed in that performance on a lot of fronts,” Gregory said. “To be honest, we didn’t do one thing very well today.”

On the other hand, the list of things they didn’t do very well covered most of the bases — shoot, rebound, make free throws, take care of the ball, play with aggression and defend.

Tech shot 29.5 percent from the field, the second-lowest rate in Gregory’s tenure. The Jackets scored 17 points in the first half, turning the ball over on nine of their first 21 possessions with misfired passes and bobbles in the face of Miami’s matchup zone defense. Often settling to shoot over the zone, Tech shot 4-for-20 from 3-point range, continuing its errant ways from long distance.

For most of the game, the Jackets couldn’t attack the zone effectively on the drive or in the post. Two of the team’s most efficient scorers, center Daniel Miller and forward Kammeon Holsey, were 6-for-10. The rest of the team was 7-for-34.

“Obviously, execution-wise, we didn’t execute as well as we need to,” Gregory said. “That means they weren’t taught the proper execution. So that goes on me.”

Tech (10-8, 1-4 ACC) trailed 27-17 at halftime, allowing Miami (10-7, 2-3) to go on an 8-0 run in the final three minutes of the half. Four of the points were the result of offensive rebounds. The Jackets remained stuck on 17 for the first four minutes of the second half, by which point the Hurricanes led 34-17.

The Jackets fell behind by as many as 18, at 41-23 with 11:34 to go, before attempting a rally that roused a home crowd that was ready to back its team, but didn’t have much opportunity. More aggressive play created baskets and free throws and reduced Miami’s lead to 44-35 with 5:23 to play. In that six-minute span, Tech could have carved away more of the lead, but missed one of two free throws on each of three trips to the line.

Tech didn’t get any closer, done in with a turnover and more missed 3-pointers.

“You’re always going to be frustrated when you’re playing at home and you’re playing against a zone and you’re not hitting shots because that’s what you have to do against a zone,” said guard Trae Golden, who led Tech with 12 points on 3-for-12 shooting.

Tech again played without guard Solomon Poole (unspecified medical issues) and forward Jason Morris (concussion).

Carter’s value as an offensive threat, rebounder and defender has been heavily underscored in the past two games. After tearing the meniscus in his left knee in the final non-conference game Dec. 29, he most likely is out for the season.

In Tuesday’s 81-74 loss to Pittsburgh, the Jackets were out-rebounded 38-18 and allowed the Panthers to shoot 56.9 percent from the field.

Only two of Tech’s 13 non-conference opponents shot better than 45 percent with Carter in the lineup. In the five league games without him, four teams have done so, a reflection of improved competition, certainly, but also the loss of Carter’s rim protection. The Jackets out-rebounded all of their non-conference opponents, but have lost on the boards in three of their five ACC games.

One player taking some of Carter’s minutes, freshman Quinton Stephens, gathered two rebounds in 26 minutes off the bench.

“It’s not like the kid’s (not) trying, but he’s in a tough matchup,” Gregory said. “You saw what Miami did as soon as he came in the game — they went right at him with Donnavan Kirk in the post.”

Still, those two losses followed Tech’s 74-69 win over Notre Dame the previous Saturday, when the Jackets held the edge in shooting percentage and in rebounding. On Saturday, Gregory mentioned the necessity for his team to play with more grit and intensity.

“We’ve got to shoot the ball better, move the ball better and we’ve just got to keep plugging away,” he said.