The Hastings-born man, who represented both clubs, died aged 33 following a crash in Poland on May 13, 2012 - two years ago today.
A Lakeside rider at the time of the accident, Richardson had previously starred for Poole in 1996 and 1999, while he also rode under Middleditch for Great Britain.
Middleditch admitted he was preparing himself for a sombre evening at Wimborne Road (7.30pm).
He told the Daily Echo: “Given that Lee rode for both Lakeside and Pirates, the timing of the meeting is a fitting tribute.
“It doesn’t seem possible that it was two years ago and the meeting is going to be a sad occasion. I suppose time is a great healer but you never forget.
“Speedway is one big family and when you lose one of your own everybody feels the pain.
“He was one of the safest riders on the track and he never took silly risks, so to lose his life in the way he did was surreal.
“I had known him since he was a baby and when he died, it hit me very hard.”
Middleditch regarded Richardson as the consummate professional and said his approach to speedway provided the best possible example for rookies in the sport.
“Lee was my stalwart when I was Great Britain manager and he never let me down,” said Middleditch.
“He was top points scorer for me and was Team GB through and through.
“There were never any questions with Lee. He put his racesuit on, was full of pride and gave 110 per cent. As a manager, you can ask no more.
“He was a rider that many young riders looked up to because he his turnout was immaculate and he was professional.
“Everything you want in a speedway rider - that was Lee.”