Rafiq scored 82 in the first innings of the first Test at Northampton
Yorkshire have suspended Azeem Rafiq for his behaviour while on England U-19 duty against Sri Lanka.
Rafiq used his Twitter page to launch a four-letter attack on coach John Abrahams after he was left out of the second Test for disciplinary reasons.
The club has suspended him while it conducts an inquiry into the matter.
Yorkshire chief executive Stewart Regan said: "Azeem's behaviour was totally unacceptable and the club will not tolerate it."
It is understood the 19-year-old all-rounder was left out of the second Test at Northampton for breaking a curfew during the first Test at Scarborough.
Skipper Rafiq is likely to face an England & Wales Cricket Board disciplinary committee.
Regan added: "Our professional players are role models to aspiring young cricketers and need to behave as such.
"Whilst Azeem has apologised formally to the ECB, the club and the coach in question, the club still intend to carry out a full investigation before deciding on what disciplinary action to take.
"In the meantime, he is suspended on full pay and unavailable for selection."