The run began with a 0-0 draw at Juve, the second-placed side they now trail by six points, with subsequent back-to-back losses to Udinese and Sassuolo contributing to the Nerazzurri being seven shy of league leaders Napoli.
Spalletti's former club Roma are just two points behind in fourth but the head coach will continue to respect Inter's obligations with regards to Financial Fair Play, given their expected return to UEFA competition next season.
"To keep saying we need to have a big transfer campaign, after the club has made it clear there are certain parameters to be respected, seems to me the best way to get hurt," he told a news conference ahead of Friday's trip to Fiorentina — Inter's last before Serie A's mid-season break.
"You can say names — Mkhitaryan, Pastore, Verdi. But they'd cost €30 million and we don't have that.
"We need to go and play our game, show all of our quality again. We need to focus on individual quality and make it available to the team. It will be needed in a match such as this.
"The players need to know that I'm absolutely certain of their quality and I know that they have potential. Things have to be fixed on their own as they have been so far.
"In these times, we rediscover the strength of the group, the family."
While Spalletti was happy to give a glowing assessment of the quality at his disposal, he warned his players that this is no time to sulk and shed tears.
"We can't make excuses. First of all, we can't cry about things. Whoever does that won't reach their objectives," he said.
"We need to improve the quality of our play a bit, we've got what it takes and I can see that. We must do something better in this regard."