Meanwhile, Rovers make the visit to the East Midlands on the back of a 5-0 demolition of second-tier newcomers Wycombe Wanderers.
Having enjoyed a solid end to the last campaign, Derby boss Cocu would have been full of optimism ahead of his second campaign in English football.
However, the Rams have not recovered from being pushed all the way by Barrow in the EFL Cup, losing their next three fixtures in all competitions.
While it could be brushed off as a coincidence, Derby's two strikes this season have both come in the minutes immediately after half time, possibly a consequence of Cocu's team talks.
The signs are there that the Dutchman is only getting short-term reactions from his players, and another defeat at the weekend would lead to further question marks being raised over his future.
Blackburn, on the other hand, have performed positively in each of their outings this season, scoring a total of 10 goals from their four fixtures.
Although narrow defeats came against Bournemouth and Newcastle United, it came as little surprise when Rovers turned those positive outings into a ruthless display of finishing against Wycombe.
Tony Mowbray has, so far, opted against making many changes to a squad which threatened the top six last season, and the continuity is starting to pay off.
Striker Adam Armstrong has been the star of the show thus far, contributing five strikes from three starts and one substitute outing.
Derby County Championship form: LL
Derby County form (all competitions): DLLL
Blackburn Rovers Championship form: LW
Blackburn Rovers form (all competitions): WDLW
Mowbray is unlikely to tinker with the Blackburn team which began the success over Wycombe.
Despite his arrival on a free transfer, centre-back Daniel Ayala is unlikely to be considered for selection until next month.
Derby boss Cocu will be able to call upon Mike te Wierik, who is available again after serving a one-match suspension.
Derby County possible starting lineup:
Marshall; Byrne, Wisdom, Clarke, Forsyth; Bird, Shinnie; Jozwiak, Rooney, Knight; Marriot
Blackburn Rovers possible starting lineup:
Kaminski; Rankin-Costello, Lenihan, Williams, Bell; Holtby, Johnson, Rothwell; Dolan, Armstrong, Brereton
We say: Derby County 1-2 Blackburn Rovers
Given his side's recent performances and results, Cocu has little option but to put more emphasis on attack. Nevertheless, that may not necessarily lead to a change in fortunes, especially against opponents who have not been short of goals.