.The England centre-forward arrived from Everton over the summer with big expectations, but has so far flattered to deceive.
Fowler has warned Leeds fans against such expectations and believes injuries have taken their toll on Calvert-Lewin.
He told Tribalfootball.com: "Yeah it's funny because we've had 11 games now and people are still talking about players bedding in. Liverpool is the same. We're talking about this with (Alexander) Isak. It is different because sports science plays a huge part of it now. The sports science people are probably telling the clubs or the managers, well, listen, you need to be careful with these.
"So they're probably stuck between a rock and a hard place, these managers, because they're listening to sports scientists who tell them that he's not quite ready. I mean it is different from years ago when if a player was only half fit he wanted to play.
"But as now everyone's telling these players, no you've got to wait a little bit. So I think that's probably what we've got to get used to with the game now."
A good player, but...
Fowler also stated, "I think Calvert-Lewin is a good player. He's a player who was linked with every top club when he was scoring goals at Everton maybe two or three years ago. You don't suddenly become this bad player.
"But again, he's probably another player who's struggled to adapt to a new club, new surroundings - although he is a Yorkshire lad.
"He's probably not the player he once was in terms of his body. But I've no doubt that you'll probably see a better Calvert-Lewin, in the latter stages of the Premier League. I think Leeds would need him to be the player that you think he is as well."
- Robbie Fowler was speaking to Tribalfootball on behalf of Adventuregamers.com