Vinicius, who scored in Wednesday's 3-0 Copa del Rey win over Leganes, has contributed either a goal or assist every 59 minutes since making his senior debut for Madrid last September.
On Isco he said: "He's fine and the rest of the available players are too".
"It is true that the appearance of young or very young players in the three-time European champions' team is always delicate, but it is a positive that an 18-year-old boy has arrived and is doing so well".
'We'll have to see who plays tomorrow, the squad list hasn't been completely decided on yet.
"I'm sure that both systems work well for us", he said.
Midfielders Toni Kroos of Germany, Marcos Llorente of Spain and Llorente's compatriot Marco Asensio, Welsh winger Gareth Bale, Belgian goalkeeper Thibaut Courtois, as well as Spanish forward Mariano Diaz continued with their recovery process from their injuries, the club said, reports Efe news. The explanations are always multiple. We've had a lot of issues, we've got a number of players out injured, but we'll be trying to get them back as soon as possible'.
Isco has been linked with a move to Juventus, which Solari also spoke about.
The players began the session divided into two rondos, where they worked on possession and pressing. "The least enjoyable part of the job is picking the team. They are players with a lot of experience, players who have been in the top level so long and won titles have the experience to know what they have to do".