「そうね、たしかに今日の春樹ちゃんは乗ってなかった感じ」「げ。そういうのって分かるのか？」

「、」「。？」

'Yeah, Haruki wasn't really into it today.' 'Ugh. You can tell that kind of thing?'

Literal

''Yes, certainly today [possessive-の] Haruki-chan [topic-は] not-riding feel'' ''Ugh. Such [possessive-の] [quotative-って] can-understand [question-のか]?''

A peek inside someone's perceptiveness. 乗ってない ('not riding') is casual/idiomatic for 'not into it, not in the zone, not having fun'. The ~感じ ('feeling, impression') at the end softens an assertion into a subjective impression. 春樹ちゃん — the ~ちゃん suffix indicates familiarity/affection. げ is a quick expression of dismay/surprise.