McIndoe has told City fans they can expect a big improvement before the start of the season.
The former Doncaster, Barnsley and Wolves man scored on his debut but could not save his team from defeat at Plainmoor.
However, the 27-year-old winger assured the Robins faithful that the squad will be ready for the season opener at home to QPR on August 11.
He told the club's official website: "We did okay but we've still got three or four more gears to go through before the season begins.
"I think it's important to realise we played well in fits and starts but there's still a long way to go and a lot to look forward to.
"We kept possession of the football without really hurting them most of the time. Perhaps we over-complicated things and passed it too much."
Sky Sports