The Hornets will do battle with the Sky Bet League One side for a second time this month after the original encounter on January 4 finished 3-3.
A much-changed Watford XI – including various fringe players and debutants – let slip a three-goal lead two weeks ago and they will face off at Prenton Park to decide who hosts Manchester United or Wolves in the fourth round.
Pearson reached the FA Cup final as a player with Middlesbrough in 1997 but, after playing at Bournemouth on Sunday and with a trip to Tottenham coming up, he feels he has little choice but to rotate his squad.
"I am paid to make decisions based on what is right for our club," he said. "I can't be sentimental. I have always been someone who has enjoyed playing in cup runs, but I am a manager so my role is different.
"My role is to make decisions based on the planning for our week. We played Sunday, we play Tuesday and we got away with managing our way through the Christmas period, which was very hectic.
"The demands of the game now are incredibly high and the players' work-rate at Bournemouth was unbelievable so we need to get the recovery right and make sure we are ready for the game on Saturday.
"This is where other players get opportunities. I don't make any excuses for it and I don't apologise for it.
"Having said that, do I have respect for cup competitions? Of course I do, but it has nothing to do with still being able to make decisions based on what I believe and what we believe as a club is right for us. Clearly Premier League safety is paramount."
Pearson insists had Watford not had so many games over Christmas, he would have played more first-team players for the first tie with Rovers at Vicarage Road.
He said: "Off the back of a very hectic Christmas period, there was no way I was ever going to put the same side out and we went 3-0 up. We should have won the game, but we didn't.
"Even with the changes which will be there, I still expect a performance and if things go our way we go through to the next round, but it is straightforward in my mind.
"I am not a player anymore, I am quite a bit older than when I played and yes the climate of what is deemed to be important is very different to what it was in the 1980s and 1990s.
"You also need to remember what the financial implications are of losing Premier League status. It comes down more to that."