Messi suffered a muscular problem while away on international duty with Argentina at the end of March, ruling him out of friendlies against both Italy and Spain.
He was then named on the bench for Barca at Sevilla last time out in LaLiga, only being deemed fit enough to come on just before the hour mark, though he was still able to inspire a comeback as they ultimately drew 2-2 having been 2-0 down.
Valverde put Messi back in his starting XI for the 4-1 hammering of Roma in the Champions League on Wednesday and seems reluctant to rest him at Leganes on Saturday.
"We'll see," Valverde told reporters at his pre-match news conference when asked about the possibility of giving Messi a break.
"He played the other day [against Roma], and against Sevilla he was rested for part of the game.
"He has had a few problems and didn't play with the national team. He's a player who wants to be active because he's the best, but we have to talk after training."
If Barca avoid defeat on Saturday, they will equal Real Sociedad's 38-match unbeaten record from 1979-80, the longest such streak in LaLiga history.
"We don't really have it in our heads," Valverde said. "We remember in these cases and they're important figures, but we're already talking about achieving it – we have to win or draw tomorrow [Saturday].
"It's a record that's been there a long time so it's difficult to match it, obviously, but we have a chance of doing it.
"Statistics vary from day to day. I'm used to winning, we're making our way and we want to reap the fruits of the season's work, now we have the most beautiful and also the most difficult [period to come]."
(goal.com)