Lampard was hooked in their 2-2 draw with Switzerland on Saturday.
"Frank Lampard is an important player," said Capello. "When he is fresh, he is a really important player.
"He has a big personality on the pitch and he scores goals. When he is in a good moment of form, he is a good player."
The problem, according to Capello, was acute tiredness which he claimed affected many of his players.
"He played a lot of games," said the England coach.
"I saw him and he was not fresh like the other players.
"I decided to make a change because of this."