It's the first time the Dutch 19-year-old has been included in a matchday squad by Marcelo Bielsa but his teenage shoulders have already felt the weight of pressure in a first-team environment at a top-flight club.
Unlike many of his peers at Thorp Arch, he knows what it’s like to not only play regularly for a senior side, but to carry an expectation.
The Dutch youngster was farmed out on loan by Feyenoord to second-tier club FC Dordrecht in December 2018, aged 17 and two months, and made an impact, scoring five Eerste Divisie goals in 18 appearances on the right wing.
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Last season he stepped up a level, again on loan, with Feyenoord’s fellow Eredivisie club ADO Den Haag.
It was at the Cars Jeans Stadion that he met Chris Powell, who was brought to The Hague by Alan Pardew along with former Leeds assistant manager Paul Butler, as part of an English-themed bid to save the side from relegation.
Pardew and his assistants were appointed at Christmas in 2019 and left four months later with top-flight status secured, albeit thanks to a reprieve. The season was scrapped due to the coronavirus pandemic.
Those four months gave Powell the chance to develop a close working relationship with Summerville, a player with exciting ability.
“I struck up a really good rapport with him,” said the England coach.
“You could see the raw talent he had.
“He’s only tiny, he’s like five foot nothing but he’s got wonderful balance.
“One v one is his strength, against players. He’s quite a free spirit out on the wing, in a good way. He’ll excite you, he’s a bag of tricks, there’s some talent there, it’s just how it’s harnessed and what the coaches demand from him.
“He’s played for the Under-18s and Under-19s for Holland so he’s well thought of in Dutch football.”
The individual skill that made him an exciting player to watch, someone who liked to go past defenders, also made him one of ADO Den Haag prime sources of creativity. The 18-year-old boy was a go-to man.
“It was a hard, difficult situation he was in because the team was struggling and they were relying on him to be the one that unlocked teams,” said Powell.
“You could see he could do it but the team was going through a very tough spell.
“He played games, he will have learned a lot from the experience.”
Losing did not come easily to the youngster, however.
“He cared,” said Powell.
“That was one good trait I felt he had. He was someone who really cared about the game.
“You could really see that when we didn’t win, which was often. He wanted us to be better.
“I suppose that impetuous side of being a young player, you have to learn all these things off the pitch, in the dressing room, they come over time.”
Speaking back in October, Powell planned to catch up with the youngster on English shores and did not rule out matchday squad inclusion this season.
“I would think they’ll give him time to assimilate,” he said.
“His English is okay, not great, it’s okay, but his talent isn’t in doubt.
“I’m sure if he’s okay in regards to communication and understands what’s wanted and they understand how he is, he’ll be fine. When you go to a new club you have to find your peer group, who you settle with and who helps you. That will be important for Cry because he’s 18, he’s still a young man. Going to the professional ranks has happened quite early for him.
“He will have to learn how Leeds want him to play, in the 23s, and take it on board. It’s an exciting signing but whether he’ll be involved in the first team I’m not so sure yet.
“Marcelo does put some young players in, it’s a small squad so over the course of the season we might see him in the 18. I hope going to Leeds United helps him to keep developing.”