Derby are sixth in the second-tier table with 67 points from 43 games, tied on points with seventh-placed Middlesbrough and a point adrift of the Robins who are placed eighth.
A win over their hosts will strengthen their place in the top-six for qualification for the playoffs.
With three games remaining in the regular season, Tomori who was named Derby County's Player of the Year on Wednesday has charged his teammates to maintain their fine form and remains bullish on his side's chances of getting the final Premier League promotion ticket.
"We have three important games. We have put ourselves in a good position and now we want to see it through to the end," Tomori told RamsTV.
"Once we get in the playoffs, we know anything can happen and that we can beat anyone.
"We have Bristol City on Saturday which is probably the most important game of the season so far.
"We want to put in a performance, get a result and hopefully we can get in the playoffs.
"And who knows what can happen after that."
Tomori joined the Rams on a season-long loan from Chelsea last summer and he has played 41 league games so far this campaign, missing just two league outings.