shorts and a cut off shirt or muscle shirt or a regular shirt
White\grey\black plain shirt(:
no
Black, white, a darker or lighter shade of grey,
14 IS ON HIS BASKET BALL SHIRT
Unless your basketball team has rules and regulations against gray colored clothing, then yes, you surely can practice in a gray shirt during basketball. There is no reason not to.
t-shirt and shorts?
light blue, off white, or teal shirt
No.
chemise grise
sure. grey matches anything
Any color shirt really, anything matches gray.