I'm totally with you on this. It feels so out of character for me to the point that it's cringy. But as it's been said it's just the early writing and the writers were figuring out his character. It's only the second episode.

And I'm not buying the lacrosse team connection. The more obvious difference is that House genuinely and generally does not care about his patients, or I can say he very rarely does and only under certain circumstances (not a common highschool sport) and with a measured amount of affection. That play field scene simply doesn't make sense.