Celtic manager Brendan Rodgers blamed the hectic festive fixture list for forcing him to ring the changes after his side laboured to victory on Tuesday night.
The Hoops, making eight changes to the side that beat Dundee on Saturday, were far from their best in the 1-0 win over Partick Thistle but ground out their 12th league win in a row to extend their lead at the top of the Scottish Premiership to 14 points.
“There’s no way I can play all the players in every game and they’ve got international games on top of that. You just can’t do it,” said the former Liverpool manager about Celtic’s schedule of nine matches in December.
“I think you have to credit the players how they have gone from game to game,” Rodgers said after Celtic extended their unbeaten domestic run to 21 matches.
He admitted his side had looked disjointed at times but with a packed programme he said he no choice but to utilise his whole squad.
“We play in a way that has a systematic approach so when one player comes in he understands his function in the team,” said Rodgers, who had also given five fringe players rare starts at the weekend against Dundee.
“I think that’s the 41st (match) we’ve had (this season) which is a phenomenal amount. And to not slip up domestically really shows that real persistence and resistance that’s in the team and the energy to keep going.”
He admitted though that chopping and changing was starting to have an adverse effect. “Naturally at times you’re going to lose a wee bit of fluency,” he added.
Rodgers handed 18-year-old winger Calvin Miller a debut at left-back Tuesday and compared him with England international Ryan Bertrand, who he converted from winger to full-back during his time as a youth coach at Chelsea.
“(Bertrand) came in as a left winger and into the same side as Scott Sinclair who was a striker,” the Hoops boss said.
“I moved Scott wide and moved Ryan in to left-back. Ryan went on to play for England and won the Champions League with Chelsea. He’s now obviously playing with Southampton and he’s an outstanding player.
“I see similar sort of traits with Calvin. But he’s only 18 so he needs time to develop. I was delighted with how he did.”
Thistle assistant manager Scott Paterson rued his side’s missed opportunities.
“First and foremost I thought the boys were very good. They kept their discipline and shape against a very good side,” Paterson said.
“It is frustrating as I don’t think a lot of teams will come here and create those kind of chances… but we have got to start taking them as they are costing us.”