The 25-year-old was pursued heavily by Spanish giants Barcelona over the summer but the Reds were adamant that he was not for sale and reportedly rejected bids in excess of £100m for his services.
Coutinho has yet to feature for Klopp's side this season, having been ruled out with an alleged back injury and an illness, but went on to feature for the Brazil national side during the international break.
"I know what people think, but Phil had the back problem a few weeks ago and couldn't train so that means he missed around about three weeks," Klopp told LFCTV today.
"Yes, he went to the national team and trained normally, but now we have to prepare for a normal season so we have seven games [before the next international break] and we saw training this morning and thought 'OK, maybe we should use him immediately' because he was really good, but that doesn't make sense.
"We have now to continue with the pre-season, not too long, but in a few sessions we have to give ourselves the time because in the next month we have seven games.
"We always have the same decision to make, 'does he need training or can he play?' and all that stuff. Yes, he will now do a little bit more than the other boys but he showed up in a very, very good mood and looks really promising."
Klopp went on to admit that he "had a really good conversation" with Coutinho upon his return to Melwood in the wake of his failed move to Barcelona.