The 32-year-old defender will be named as a substitute in today's FA Cup semi-final clash with Manchester City after playing for the Blues in their victory over Rubin Kazan in the Europa League on Thursday.
Benitez feels that Terry is at a point in his career where playing two high-profile games in the same week is proving difficult.
"With his age, he has more experience and his understanding of the game will be better but you have people coming that will be faster and they will be stronger," Benitez told the Daily Mail.
"But still he has a lot of ability and he can do well. But it will not be two games a week, carrying on playing, because you have more competition [in the squad]. His age is fine. It's not a bad age. But you have someone coming with 25 and the other with 28 and they are pushing and pushing, so you have to compete.
"And this is the main thing: if you play two games a week it's not easy to keep at the level. [If it is] in a normal team then fine, but in a top side where you have to win every game, it's not easy."
Both Benitez and Terry were forced to deny rumours of a bust-up between the pair earlier this year after reports claimed that they had fallen out.