New Delhi, Sep 26 : England assistant coach Marcus Trescothick has encouraged Jason Roy to maintain a positive outlook despite being left out of the ICC Men's World Cup squad. Initially, Roy was part of England's initial 15-man squad for the 50-over World Cup defense in India. However, a late change saw Harry Brook taking his place. Due to recurring back spasms, Roy couldn't participate in England's recent four-match ODI series against New Zealand, leading selectors to opt for Brook as a more secure option. "I've not spoken to Jason, he's surely disappointed but you've got to remain positive that he can still make an impact. Reserves have a big part in World Cups. You pick up one injury and someone comes in, they could come in and make a hell of a lot of runs. If he keeps himself fit and ready to go, should we need him to come out then we'll make that call," Trescothick was quoted by Sky Sports. Following his disappointment of being snubbed from the World Cup, Roy declined the opportunity to represent England in the three-match series against Ireland, a decision that raised concerns about his future with the national team. "It was a good opportunity for him to play a longer innings and play a bit more. We know how much of a talent he is, it's his opportunity - getting the chance to play is going to be the real challenge for him. It's a good team, trying to break into it is tough," Trescothick added. Roy has shown remarkable performance in ODIs this year, maintaining an average of 46.33 and a striking rate close to 100 in six matches. He played a crucial role in England's historic victory in the 2019 ODI World Cup held in their home country, amassing an impressive 443 runs at an average of 63.28 and a strike rate of 115.36, including a century and four half-centuries. Meanwhile, Brook has struggled in the 50-over format, averaging a mere 20.50 in six games, including a dismal series recently against New Zealand. England will play their final ODI against Ireland in Bristol on Tuesday, before facing New Zealand in their World Cup opener in Ahmedabad on October 5. /IANS