Ousmane Dembele is close to recovering from an ankle injury. Although the statistic is quite staggering, Ernesto Valverde, will be wary of what the over dependency on one man can cost as we progress to the end of the season.
Against Sevilla, they went all out last week to claim a 6-1 win and turn a first leg's deficit in the Copa del Rey, whereas over the weekend, they had to come from two goals down to pick up a point against a resolute Valencia side.
The Spanish giants return to Champions League duty against Lyon and Valverde will want Messi fit to play the unsafe French side, who inflicted a first defeat on leaders Paris St-Germain last weekend.
"In football, it's always best that the best players play in every game, that's just how it is", Solari said.
Valverde added: "It is true that sometimes we have had doubts with players and we have waited until the last moment, and it's the same with Messi".
The Barca coach will then have to decide whether Messi is fit enough to start the game. We'll make a decision based on that. The club has yet to release a full medical report on the injury, and he didn't practice with his teammates on Monday. Solari has all of his best forwards, including an in-form Karim Benzema, the quickly maturing Vinicius Junior, and a fully fit Gareth Bale.
He missed Barcelona's 5-1 league rout of Madrid in October because of a broken right arm.
Barcelona have a tight grip on this competition having won the past four finals to take their overall number of Copa del Rey triumphs to 30 - more than anyone else. "I don't think there is a favorite in a semifinal between Barcelona and Real Madrid".
Barcelona weren't keen on risking Messi in the first of their three upcoming matches against their arch-rivals this month and wanted to rest him.
"It is nearly impossible to stop the competitor Messi if he wants to play".