The Ukrainian striker, who joined the Blues in 2006 in a £30million move from Milan, struggled in his first year in England and he has found first-team football increasingly hard to find this season.
Grant, who replaced Jose Mourinho as Blues boss earlier this season, has previously stated that Shevchenko is part of his plans at Chelsea.
Grant has suggested he is unlikely to race into the January transfer window in order to plug the gap left by Drogba and Kalou because he already has replacements at his disposal.
"One of the reasons why I have not rushed to make a decision on signing during the African Nations Cup is we have good strikers here in Shevchenko and Claudio Pizarro," said Grant in the Daily Express.
"They are in the squad because they will be useful during that period, but not just then. I want him (Shevchenko) to be useful this month as well.
"He is not depressed. I can only judge players by what I hear when they speak with me or what I see in training. He is happy in training and he is training very well.
"When you come to a big club and you have so many big strikers, sometimes there are big names that don't play for a period of time."