Few know better than Thompson, enjoying his first season as Bacup skipper, just how much influence the West Indies star can have on a side.
Harper enjoyed eight superb seasons at Lanehead and left behind some wonderful memories as well as earning the greatest respect from players like Thompson who felt privileged to be in the same side.
Tomorrow at Seedhill, Bacup take on Nelson and their former professional and know just how tough a task they face.
But Thompson declared: ``The title race isn't over yet. It could still be wide open with a lot of cricket to be played.
``If someone has a good run and Nelson lose or draw a couple of games everybody could be back in with a shout.
``I don't think it's a foregone conclusion. ``But Roger is having a superb season. These conditions are perfect for him and on wet wickets he is virtually unplayable,'' he added, speaking from the middle at Seedhill where he had gone to check on the state of the wicket yesterday.
Yes, it was wet through!
When the teams met earlier in the season the weather intervened, but Bacup are prepared to meet the challenge they anticipate tomorrow.
``It's going to be an experience. When he was at Bacup, we always said we wouldn't have liked to play against him,'' the skipper explained.
``He's a top-class performer and he did a lot of good for Bacup. ``All the lads are keyed up for this one.''
Harper had a big influence in bringing along many members of the present side but Bacup are also pleased with the way things have been going for their present professional Brad White.
``He is an outstanding batsman, a class act,'' said Thompson. ``I think he's got around 630 runs and nearly 40 wickets.
``You only have to look at everyone else's performance to see how good that is and he really likes it here.''
Tomorrow's fixtures: Accrington v Haslingden; Burnley v Enfield; East Lancs v Colne; Nelson v Bacup; Ramsbottom v Lowerhouse; Rawtenstall v Church; Todmorden v Rishton.