Rooney criticized Bruno Fernandes for not tracking back during Manchester United's Champions League comeback win over Roma.
Speaking at halftime, Rooney said the team was "all over the place" and expressed shock at their poor first-half performance.
Asked whether the first half was a "new low" for his former club, Rooney said: "Yes, there have been plenty of low moments recently, but this is certainly the lowest.
You're playing in the Champions League, and there's been a lot of discussion and criticism about this team. People would expect some kind of response, but there was nothing, absolutely nothing.
Roma were more aggressive when they won the ball, and nobody from Manchester United pressed them. They really struggled on the left flank.
You just want to see something, some fight, effort and desire to win, but there was nothing.
For the first goal conceded, if you play a system where Dalot pushes forward, Bruno should cover that position. He has to track back. You are the captain, so get back and defend, and take responsibility.
You are a team and must play as a team. When a teammate is out of position, even if you don't want to go there, even if you don't want to track back, you have to go back.
I really feel sorry for the fans, because they don't know what to do. It has been many years since they were in this situation, and they don't know whether to keep supporting the team or put pressure on them. I really feel for them.
This team has lost its way. No confidence, no belief, the team is all over the place."
After the final whistle, Rooney added of Manchester United's comeback victory: "The second half was fantastic. They played further forward and ultimately deserved to win the game.
The first half was terrible, but in the second half we saw the fight and effort we wanted. The fans were fully behind the team, and you felt they could go on and win this game."
Former England international Shearer said: "Carrick deserves immense credit, because they were on the verge of elimination at halftime.
They were a mess in the first half, and he had to adjust and fine-tune a few things.
I don't know exactly what he said, but he must have started in the dressing room, pointing at a few individuals and telling them to be braver, show more courage and pass the ball faster.
They did all of that in the second half, and they reaped the rewards by securing the victory."