Barcelona president Josep Maria Bartomeu has revealed he would contact Real Madrid chief Florentino Perez before swooping to sign misfit Isco.
Messi did not play in the most recent Clasico between the sides at Camp Nou last October due to an arm injury, but Barca ran out 5-1 winners regardless.
"This year is also an important one for the strategy of establishment of Barca in China, which will experience its most important moment next summer when the first team will visit China and Japan on their pre-season tour". The Catalans will be looking to gain first leg advantage in the Copa del Rey semi-final against their arch rivals as they bid to win a fifth successive cup title.
Valverde can only name 18 players in his final match day squad, though, so one player will have to miss out.
Real Madrid coach Santiago Solari said the uncertainty about Messi wasn't affecting his team's preparations.
Lakers Offer New Trade Package for Anthony Davis
The Lakers have reportedly already made an offer to the Pelicans, but were basically laughed off the phone without a counteroffer. Davis's father, Anthony Davis Sr., has also come out and said that he doesn't want his son playing for the Celtics .
They arrive for the first-leg match at Camp Nou enjoying their best period of the season and with almost all of its players available. Solari has all of his best forwards, including an in-form Karim Benzema, the quickly maturing Vinicius Junior, and a fully fit Gareth Bale.
"I don't think it changes anything", he added when asked how a hypothetical Messi absence could influence proceedings.
"It is nearly impossible to stop the competitor Messi if he wants to play".
In addition, Frenchman Ousmane Dembele returned to training on Tuesday after battling hamstring injury in the past days.
Real Madrid also have the small matter of the Madrid derby not to mention Champions League fixtures against Ajax in a hectic schedule.
The quality and intelligence of the players allow them to pass the ball very quickly without running too much - something brought to the club by Pep Guardiola that the following managers were clever enough to keep.