When he gives you an invitation to watch or play sports and extends the same invitation to his other friends, it is rarely a date, especially when this is the first social meetup with him.
A man that is romantically interested in you naturally wants to do something with you on a one-on-one basis to determine whether there is romantic chemistry without distractions.
In going on multiple dates with you and determining romantic chemistry, he naturally wants to introduce you to his friends, having already informed them of his romantic interest in you.
In this scenario, he invites you to watch or play sports so that you get to meet his friends, who are now eager to meet you, given everything he has already told them about you.
Secretly, he is attracted to her and hopes that his friendship with her leads to a romantic relationship in the foreseeable future.
As the weeks give way to months, he becomes obsessed with this wish.
Every time they talk, he searches for clues in what she says and her body language to determine whether she is finally ready to admit that she likes him.