Replacement
Disclaimer: No, in the four days since the last manga chapter I have not managed to get the copyright permit to Naruto. It still belongs to Masashi Kishimoto.
They didn't know he was watching. That was the only possible explanation. Whenever he looked at either Naruto or Sakura these days, a warm, loving smile would appear on his teammate's face. They would try to reassure him without words that they forgave him, the past was behind them, and they were Team Seven again. The paper Tsunade had handed him said as much, but it wasn't official, it didn't mean anything, until Naruto and Sakura agreed. They'd been smiling to prove that they did, to say that the still loved him. Every time he looked at them, there had been a smile.
Except for now.
Now, he was looking at them, and they were smiling. But it wasn't at him. Naruto was arguing playfully with a dark-haired man, and Sakura was looking on with an indulgent smile that was half annoyance and half love. It was a scene straight out of his childhood, except for one key difference:
It wasn't his.
That dark-haired boy wasn't him. The insults being called back at Naruto weren't "dead last" and "clumsy idiot." The face Sakura was smiling at wasn't his. It was a new face, a face that should never have been there. It was a face that was only supposed to be a temporary addition to Team Seven. The face of Sai.
There was one other difference from the Team Seven of his youth: Naruto and Sakura. Back then, there had been a trace of real anger underlying Naruto's insults; there had been a faint edge of desperation in the way Sakura smiled at him. There was none of that here. This Team was pure.
And Sasuke couldn't help but wonder if the Academy teachers had gotten it wrong when they assigned teams all those years ago. Naruto and Sakura were obviously meant to be teammates, but he couldn't' help but wonder if they'd gotten the third team member wrong. Maybe Sai wasn't the replacement on Team Seven.
Maybe it was Sasuke himself.