Messi, 33, is one of 25 players called up by Ronald Koeman for a friendly against third-division side Gimnastic de Tarragona at the Johan Cruyff Stadium at the Barcelona training ground.
However, there's no room for either Arturo Vidal or Luis Suarez. Koeman has told both players they are not in his plans for the upcoming season, and sources have told ESPN their exits could be confirmed next week.
Messi, though, will be staying at the club. He returned to training on Monday after telling Goal that he wouldn't be pursuing the necessary legal action to try to force an exit.
"It's great, everyone knows he's the best player in the world, so to have that player in your team is exceptional," Koeman said on Friday of Messi's decision to stay.
"For us, it's now very important to have Leo in the best conditions to play. There's no question about his quality, and it's fantastic that he'll be part of the season with Barcelona, everyone is really happy about that."
De la Fuente, 19, could be in line for his first minutes with the senior side. The forward was an unused substitute in the Champions League win over Napoli in August and has been training with the first team since Koeman was appointed.
The Miami native joined the club's academy in 2013 and has come through the ranks since. He was part of the B team that just missed out on promotion back into the second tier of Spanish football in July.
Ousmane Dembele also returns to a match squad for the first time since November after recovering from a knee injury, but Marc-Andre ter Stegen, Samuel Umtiti, Miralem Pjanic all miss out due to fitness issues.