Smuda dropped Tomasz Jodlowiec, Michal Kucharczyk and Kamil Glik in the wake of Saturday's 1-0 friendly win over Slovakia.
"It was really painful to tell three players they will not participate in the finals," explained Smuda at a press conference.
"Saturday was very difficult for me. We played a friendly and I was praying the whole game that none of my players would get injured.
"Then, in the evening, I had a meeting with my assistants, captain Jakub Blaszczykowski and with the three players. I understand they are disappointed, but two months after the Euro finals we start our World Cup qualification campaign, so they can return if they make progress."
Poland kick off their Euro 2012 campaign on June 8 against Greece. They have also been paired with Czech Republic and Russia in Group A.
|Jakub Wawrzyniak||Legia Warsaw|
|Grzegorz Wojtkowiak||Lech Poznan|
|Jakub Blaszczykowski||Borussia Dortmund|
|Maciej Rybus||Terek Grozny|
| Rafal Wolski