Barkley was withdrawn before the 90 minutes were up for the fourth game running against Leicester and failed to provide the creative spark needed in the absence of injured talisman Jack Grealish.
"It's a long way off the mark to say things aren't working out for him," Smith reiterated, with a reporter suggesting things aren't quite going to plan for the England hopeful. "He had just been substituted after 73 full minutes.
"His numbers have been really good in terms of his output on the pitch and we have to remember he's been out for six or seven weeks with a hamstring injury and then had to play games to recapture that fitness because we haven't been able to train.
"But he's certainly getting back to where we want him to. I just needed to change the game at that time."