Messi has endured a difficult start to the season due to injury problems, suffering a calf strain in August that kept him out for a month, before a hamstring issue struck against Villarreal in September.
Early indications seemed to suggest Messi was going to be missing for up to three weeks, but he was back in training on Monday.
Although Valverde is yet to decide whether Messi is ready, he did warn expecting fans that he shall not needlessly risk their talisman, while there also remains a little uncertainty around Ousmane Dembele after hurting his hamstring.
"We will see if he [Messi] receives it [the all-clear to play]," Valverde told reporters on Tuesday. "First we have training. What I reiterate is that we will not run any risk and we have to wait for training.
"On Monday Dembele did the first part of the training, so now we see if he can do more on Tuesday.
"Leo did half the training on Monday, we'll see if he can finish [Tuesday's session]. I don't know if we can count on them in the end."
Barca began their Champions league campaign with a 0-0 draw at Borussia Dortmund, meaning they are under a little more pressure to get a home win against Inter.
Ernesto Valverde: "Inter Milan have changed a lot, with new players and a new manager, and they're playing a different scheme. So, last year's game can only help us so much." #BarçaInter pic.twitter.com/A9hFMOlKdp— FC Barcelona (@FCBarcelona) October 1, 2019
Antonio Conte's side have enjoyed a stunning upturn in form since the former Chelsea coach took over, winning six and losing none of their seven matches across all competitions this season.
In last season's Champions League, Barca beat Inter 2-0 in Camp Nou and drew 1-1 in Milan, though Valverde expects an entirely different challenge this time around.
"It is a team that has changed many things; players, the coach, they're playing with a different system, even if there are similar things, such as their intention to push up," Valverde said.
"They have had a spectacular start, they are winning all their matches and we are waiting for a complicated game.
"This is another Inter to last year, impacted by the coach, something similar to what we met with Chelsea two seasons ago. It's a solid team, hard to score against."