"I don't think anyone can disagree that this is the right way to handle Jermain,'' says the Hammers boss.
"To bring him on later on, when the game becomes more stretched and the opposition are tiring, is the right way - we've proved that time and time again this season.
"He may well start a couple of the last seven matches of this seaosn and next season he'll be ready to compete on a level playing field with all the other strikers at the club.
"I just happen to think that, in England, we have a bad habit of throwing young players in too early and too often. I didn't see any 20-year-olds playing for Italy on Wednesday night, and it's the same with the Dutch and the Spanish. They protect their young prospects, keeping them in their own age group, until they are fully ready to step up permanently and enjoy 15 years or so at the top level."
Defoe, 19, scored the third goal to make it 3-1 and finally kill off the second half comeback hopes of Ipswich Town on Saturday.
The victory put West Ham on 40 points, the benchmark for all clubs seeking to avoid a relegation scrap, but Roeder vowed to keep up the momentum until the final game.
He says: "We had a meeting with all the players yesterday, when we made it clear that we want to see desire from them from now right through to the last game against Bolton. I told them that this is the key month of the season when prizes are won and lost, and it's when the really big players show themselves for what they are."