However, there is no danger of Tigers grinding to a halt during a demanding spell that will test every club's squad resources.
Howard said: "I will change the whole starting XV from the Bristol game to the Irish match.
"We have been preparing for this period since August, and we knew how hard this spell would be.
"Some individuals could come through two games in four days, but you talk about player welfare, and it is important to look after the guys. If we can afford to do it, we do it.
"This spell will be a tough test on everyone's squad and, if we have done things right, we can come through it well.
"Most of those guys involved against Bristol will go out again in eight days' time (against Saracens) feeling well rested and in a good position to play again."
Leicester head to Reading on Tuesday having won six out of seven Premiership games, and they last suffered a Boxing Day defeat against any opponent when the Barbarians toppled them in 1970.
Irish, meanwhile, have gone more than three years without beating Leicester, and their only Madejski Stadium league win this season came against Northampton last month.