Rotherham moved up to fifth in the second tier with their narrow win over Doncaster in the Yorkshire derby last Sunday.
A further victory over third-place Nottingham at Clifton Lane today could see them overtake their opponents depending on the points spread.
But as it stands going into round 11 of 22, only 16 points – effectively four wins – separate Nottingham in third and Doncaster in 11th.
“The league this year is tighter than it’s ever been,” said Blackett, whose side reached the promotion play-offs last season after residing in the top four for the entire campaign. “Anyone down to Doncaster in 11th can still get in. If a team goes on a run of three, four or five wins then you can really shoot up the table.
“We’ve seen it already with Bedford and Yorkshire Carnegie being on the rise. It shows how competitive the league is and that there are no freebies.
“Last year there were maybe six teams in the shake-up but Cornish Pirates faded around this time before London Scottish eventually dropped off the pace.
“This year, apart from Bristol and Worcester who are the top two, it’s wide open.”
Doncaster’s focus is on securing enough points to ensure they finish above Plymouth Albion in the relegation position, but Blackett believes even their Yorkshire rivals can still be a factor at the other end.
“We saw last week how good a team Doncaster are,” said Blackett. “They were very competitive and anyone can beat anyone in that 11th to third bracket.”
Nottingham arrive in Rotherham having won their last two games, while Rotherham have lost twice in succession at Clifton Lane.
“We’re proud of our record at home and we want to get back to it,” said Blackett, who has hooker Tom Cruse back after a successful appeal against his Boxing Day dismissal.
Jack Preece is fit after coming through the concussion protocals while Jack Roberts has returned to the club on a three-week loan deal from Leicester Tigers, the club he joined in the autumn.