Derby are one of the favourites to finish in the Championship top two this season and gain automatic promotion to the Premier League.
The Rams suffered a spectacular collapse in the second half of last season and failed to even end up in the playoffs.
Steve McClaren was in charge of Derby then, but could the same thing happen under Paul Clement this campaign?
“The way they blew up last year could still have an effect on them,” Holloway told Sky Sports. “Was it the speculation about Steve McClaren leaving last season that was to blame, or was it deeper than that?
“Things might be more stable now with Clement in charge, but the question is: do they have the mental capacity to go on and become champions? I'm not sure.”
Holloway has also pointed out that defensively Derby are vulnerable, claiming that Middlesbrough and Hull City do not concede goals like the Rams do.
“There is a clear weakness in the Derby defence - they've got a soft underbelly and I'm not sure they've got enough cover in that area,” the former Queens Park Rangers boss told Sky Sports.
“Jason Shackell is a fantastic player, but Derby concede goals that a team like Middlesbrough or even Hull wouldn't concede - in big games too. Have they got the mentality of champions? That's their Achilles heel.”
Derby are third in the Championship table at the moment with 49 points from 27 matches.
The Rams are six points behind leaders Middlesbrough, who have a game in hand, and four behind second-placed Hull City.
Clement’s side have not won a Championship game since Boxing Day and will take on Burnley away from home at Turf Moor next week.