The Robins have been left with a record of won four, drawn four and lost four, lying 14th in the table.
"Concern is the wrong word because I have belief in the group and what we are trying to do," Yates said.
"It’s just a case of turning our current form around because last Saturday was disappointing.
"The players need to perform this weekend and we need to start picking up results, but I have been relatively happy with performances.
"We have not been getting the results and it’s now time to do something about it."
Yates was left to rue defensive errors in the second half of last Saturday's 3-1 defeat at Shrewsbury Town as a lead quickly evaporated after Byron Harrison's opener in the 48th minute.
"This season we haven’t made too many errors, but we did against Shrewsbury and it cost us," he said.
"We have to tighten up and you can’t really legislate for individual mistakes, but we didn’t do enough as a team to get three points at Shrewsbury.
"We took the lead and just gave it away so we have to respond now. We looked jaded in the second half and it wasn’t up to standard.
"Training has been sharp since then and we have to get over the tiredness and give them a breather, but also make sure they are doing enough and get that balance."
Despite their recent slump, Cheltenham made a superb start to the season and Yates remains adamant they are a much-improved team when compared to last year.
"We are a better team than we were last year, a far better one" he said. "We’ve had meetings with players and there is definitely genuine belief within the group.
"We're only three points off the play-offs so it’s not all doom and gloom and we are more aggressive this season, you can see that with the bookings we have got. I am not patting the lads on the back for that, it’s just a fact.
"We are also more clinical and more ruthless, but we are all frustrated that results haven't matched the performances."
Cheltenham face a Northampton team currently sitting ninth in the table, five places above the Robins.
"Northampton are tough to beat, but they have a few injuries at the moment," Yates said. "They can play in a couple of different ways and we know the strengths of Kaid Mohamed and Chris Hackett, who tore us apart in the play-off semi-final at their place.
"They have some good players and threats, but we think we can hurt them. Marc Richards is out, which I am glad about because he always seems to do well against us."
Defenders Lee Vaughan and Steve Elliott are both expected to have shaken off impact injuries to take part against Northampton.