Alpha Tauri's two drivers bear "scars" from their premature promotions to the senior Red Bull team, according to team boss Franz Tost.
"My drivers have some proverbial scars, but they are also grateful for the opportunities they have," Tost told Tiroler Tageszeitung newspaper.
"Pierre Gasly and Daniil Kvyat simply went to Red Bull too soon. This was not the intention," he explained.
"They would not have been promoted otherwise."
Meanwhile, Tost tipped Max Verstappen to be a serious title contender in 2020, and also backed former Toro Rosso driver Sebastian Vettel to thrive this year.
"Verstappen has all the ingredients a champion needs," he said. "A huge dose of talent, unlimited passion, unprecedented discipline and creativity on the circuit," he said.
"With Verstappen, Red Bull can definitely compete with Mercedes."
As for Vettel, Tost added: "If he is not treated negatively by Ferrari, he can win races. He can also make it very difficult for Charles Leclerc.
"He is not getting younger, but Vettel is still very fast."