Hearts substituted Joaquim Adao at half-time against Rangers because referee John Beaton was ready to red card the Angolan midfielder.
Adao was cautioned after 19 minutes – his fourth booking in four Hearts appearances – and committed two further fouls before the interval.
Beaton made it clear he would be ordered off with one more indiscretion, so Hearts manager Craig Levein replaced him with Prince Buaben for the second half.
Hearts lost the match 2-0 to goals by Jamie Murphy and Russell Martin, their case not helped by the enforced removal of the on-loan Sion player after 45 minutes.
Levein told the Evening News he was concerned about going down to ten men at Ibrox, but also about the prospect of Adao missing vital upcoming league and Scottish Cup matches through suspension.
“I had to take him off at half-time because the referee had said: ‘One more tackle and I’m sending him off.’ I can’t afford to lose him. We’ve lost Arnaud Djoum to injury and we can’t afford to lose another midfielder,” said Levein.
“We brought Joaquim in because he’s competitive. I don’t want to to quell any of that competitive nature, but he just needs to be careful.
“I think he likes the football here. He likes the second-ball scenarios where you’ve got to anticipate and be aggressive. He can tackle as well and he likes tackling. With losing Arnaud, I worry about what I would have left if Joaquim wasn’t playing.
“I just wanted to keep him available. I want him available for tomorrow night against Kilmarnock and I want him available for Sunday against Motherwell in the Scottish Cup.”
Striker Steven Naismith only managed the last 17 minutes as a substitute against his former club, but he is expected to be fit to face another of his old employers, Kilmarnock.
“Naismith only trained a little bit on Thursday and a little bit on Friday. It wasn’t full sessions,” revealed Levein. “It was good for me that he got nearly 20 minutes and in his mind he will feel good about getting some game time after being out with his hamstring. I’d expect he’ll be fit to play tomorrow.”
Levein admitted Hearts were fortunate to leave Glasgow with only a 2-0 defeat. A series of saves by goalkeeper Jon McLaughlin prevented them suffering a much heavier loss.
“Truthfully, we probably got away with one,” said Levein. “Our goalkeeper was excellent, John Souttar had another excellent game, and Christophe as well. Our best players were probably defenders so that tells you much about the performance.
“I felt we missed a little bit of composure. Any time we did show composure on the ball and pass it, we looked like we might get something. We also missed a couple of chances but they had more opportunities to score than we did.”