The former England international was sacked in February this year with the Terriers sitting third in League One.
Clark’s dismissal caused a major stir nationally but chairman Dean Hoyle’s decision was fully vindicated by Huddersfield going on to win promotion via the play-offs in May.
Manager Grayson said: “The game is of no extra significance than any other. If it is for Lee, I don’t know. But, from our perspective, it is all about getting the three points and bouncing back from a disappointing week.
“What happened between Lee and the club happened. The club made the decision and that is that. But I am grateful for the players Lee left behind.
“Obviously, we have added some good players since then but it is also worth adding that Lee was one of the first to call me when I got the job last season. To me, that said a lot about him.
“I did enjoy going back to my old club when we played Blackpool. It was my first time as an opposing manager. But the key is you look forward and not back. I am sure Lee will be doing the same this weekend.”
Back-to-back home defeats have tempered some of the euphoria that had been built by wins on the road at Sheffield Wednesday and Blackpool.
The manner of Tuesday’s reverse to Leicester, in particular, led to questions being asked as to whether Huddersfield can last the pace.
Grayson, however, points to the topsy-turvy nature of the Championship. He said: “I saw a statistic the other day that said of the last 36 matches in the Championship, there were only five home wins. That says it all about the Championship.
“That is why no-one should be down-hearted after what has happened in the past week. We have shown already that we have the quality to bounce back.
“If anyone needs an example as to how quickly things can change, just look at Birmingham. They lost heavily at home to Barnsley but then the following week beat the leaders (Brighton) away.”