Lita has spent the majority of the season out on loan at Norwich and appears certain to leave the club before his contract expires in the summer.
He was given a hero's reception by the home crowd when he came on as a late substitute and scored his first goal at the Madejski Stadium since February 2007 with two minutes remaining to seal the rout which lifted the Royals to within four points of leaders Wolves.
Norwich are just one club who are keen to take Lita back on loan this month but Coppell refused to comment on his future.
He said: "It's no headache for me to have four strikers, I can assure you of that.
"It's a nice position to be in, my strikers are uncomfortable which is what I want. Noel Hunt and Kevin Doyle both scored but so did Leroy so they can't relax.
"Leroy always gets a great reception here. I have no plan as such with him.
"He just wants to play football but I have two strikers who are in form and scoring goals so in the short term he is not going to start for us.
"But he has put Kevin and Noel under pressure now and if they don't produce the goods then I will put him in."
Coppell admitted his side were not at the best during a first half littered with errors until left-back Chris Armstrong put them ahead.
Two goals in a minute from Hunt and Doyle then killed the game off midway through the second period and leave Coppell thankful for his strike force.
He said: "The result was better than the performance. We had a few players who have had a bit of time off and we needed that game.
"Getting the first goal was critical because we were getting a bit jittery and that was affecting our play.
"We are capable of killing teams off within a few minutes. Sometimes you wish you can click your fingers and it would happen but you have to probe for openings and we have good finishers here."
Watford boss Brendan Rodgers felt his side played their part until Armstrong's goal but admitted that some of the defending was not good enough.
He said: "There were aspects of the game I was pleased with. We played well and dominated possession until the goal and then we had a crazy minute in the second half where we gifted them two goals.
"You cannot do that against a quality side like Reading who will go up for sure this season.
"Defending has been our Achilles heel all season, even before I came here and we seem to take one step forward and two steps back."
Rodgers also dismissed speculation linking midfielder John-Joe O'Toole - an unused substitute - with a move to leaders Wolves.
He said: "I've had no bids for any players. There is going to be speculation about John-Joe as he is a top young player but I have nothing to report on that."