感恩您的提问

不可以说 sport club. sport 作为体育运动是不可数，作为体育运动项目（a particular form of sport）是可数名词，sports club 是包含多项体育运动种类的，所以用的复数。

希望解答了您的疑问。

可以用单数，多见于英国英语，但复数更普遍。请看几个使用单数的外媒例句：

The specific structural conditions of a sport club are subject to change by the corresponding impulses of the members.

The spirit of the 19th century private, single sport club was commodified rapidly in the late 20th century. 

The challenge for any local sport club is to build an environment where learning is central and knowledge is distributed across all members. 

Usually, a talented youth handball player both practices and plays with different teams within his or her sport club during the same training period.