Grealish was a surprise omission as he paid the price for falling out of favour with City boss Pep Guardiola during their charge to the Premier League title.
Maddison said he was “devastated” to miss the tournament in Germany following a lacklustre end to the campaign with Tottenham.
Rice felt the pair’s pain after becoming close to them in recent years on England duty.
“It’s been really tough. Madders and Jack are two of my best mates in the squad, probably spent most of my time with them since I’ve been here,” Rice told reporters on Thursday.
“To see them go is not a nice feeling. And they’ve both just said then, before they went, Madders last night, Jack just now, that they wish us all the best.”
Grealish had been regarded as one of England’s brightest talents when he featured during their run to the European Championship final in 2021.
He was also involved at the World Cup in Qatar two years ago and shone in City’s treble-winning season in 2022-23 before losing form this term.
‘We’re so close as a group’
Maddison went to the 2022 World Cup with England and was a regular in the squad throughout the qualifying campaign for Euro 2024.
“They’re gutted they’ve been left out of the squad. We’re so close as a group and no one is feeling really bitter about being left out,” Rice said on the eve of Friday’s final Euro warm-up against Iceland at Wembley.
At just 25, Rice is the oldest midfield option in the squad, but he believes Southgate’s decision to select Kobbie Mainoo and Adam Wharton could prove a worthy gamble.
Mainoo, 19, scored for Manchester United in their FA Cup final win against Manchester City in May to cap his breakthrough season.
“I think we saw in the last camp against Belgium and Brazil what Kobbie could do,” Rice said.
“Obviously the last six months, all season really, what he’s done at Man United and he clearly deserves his place in the squad.”
Wharton has also caught the eye in an even more meteoric rise since the 20-year-old move to Selhurst Park from second tier Blackburn in January.
“Adam played his first half of the season in the Championship, came to Crystal Palace and has been outstanding,” Rice said.
“In training he’s impressed a lot of players, he is so composed and calm on the ball. He’s got a beautiful left foot, just a really down to earth boy.
“He still is obviously only 20 years old but to be on the plane to go to his first European Championships, what a moment for him and his family.”
England start their Euro campaign against Serbia in Gelsenkirchen on June 16, before facing Denmark and Slovenia in their remaining Group C fixtures.
© Agence France-Presse
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