Tottenham Hotspur boss Mauricio Pochettino said experimenting was best left to scientists, as he bristled at a question on whether he would use Sunday`s Premier League clash against Newcastle United to tinker with his starting lineup.
Struggling Newcastle were beaten 1-0 by Arsenal in their opener before losing 3-1 at promoted Norwich.
Asked on Thursday if he would experiment with his team ahead of next week`s visit to Arsenal, Pochettino told reporters: "Experiment? I`m not a scientist. I`m not a chemist."
"You`re talking about experimenting. That`s in some room outside of this training room. We`re coaches and we do our job, we don`t experiment. We train people that have the ability to play football ... that`s it."
"Don`t compare us with doctors or people in university studying a lot. I have a lot of respect for the people who do what you say, experiment, to help life. But for us to find solutions, only I`m a football coach."
Argentine Pochettino said his compatriot Giovani Lo Celso, who joined on loan from Real Betis in the close season, was a long way away from full match fitness.
"Lo Celso is a situation that`s not going to be easy. He was in extended holidays after the Copa America, he didn`t have a proper pre-season and didn`t train much. He then signed for us after a week without training," Pochettino said.
"He`s training well but is so far away from what we expect from him. We need to give him time and we won`t expect too much from him."
Midfielder Dele Alli could feature against Newcastle after missing the start of the campaign with a hamstring injury, while forward Son Heung-min is available after serving a three-match ban that was carried over from last season.
Record signing Tanguy Ndombele is out of the contest after suffering a minor thigh injury during training.
Pochettino was unsure if midfielder Victor Wanyama would remain at the club beyond the European transfer window which ends on Sept. 2, having fallen down the pecking order.
"Football is not about yesterday. It`s about today and you need to show everyday. Victor was injured and others stepped up," Pochettino added.
"We`re not a charity, not in this case about Victor, but we have a lot of options to play different players and sometimes players are lucky, some are unlucky."