Mark Warburton defended his second half substitution of Rangers’ goalscorer Emerson Hyndman following the 4-1 defeat to Hearts, after the decision was booed by the away fans at Tynecastle.
The American loan player from Bournemouth netted the equaliser on 36 minutes and went close again just before half-time.
He was one of the better performers in the Rangers ranks, if not the best, and fans were audibly annoyed to see him depart the field on 60 minutes after the away side had slipped into a 3-1 deficit.
Warburton said the decision was purely a fitness issue as he felt the midfielder may do himself harm having played 90 minutes in the 2-0 win over Motherwell last Saturday.
The Rangers boss said: “He is 20 years old, hasn’t played many 90 minutes and on Saturday he played an outstanding 90 minutes. He is a young, precocious talent and Saturday took a lot out of him.
“The pitch out there is so heavy. We’ve got a responsibility to his parent club. We have got to look after their asset.”