Manager Chris Wilder expects new players to join Sheffield United "in the next week or two" as he puts his side through their paces in pre-season in Portugal.
Wilder's side, who have been put through two sessions a day in the heat after landing in the Algarve, took part in an open training session for their fans today before taking on Portuguese top flight outfit Maritimo tomorrow evening (7pm local time).
And with Wilder still chasing reinforcements following David Brooks' move to Premier League side Bournemouth, he said of his side's mental strength: "It's important because there will be times throughout the season when they need each other, and we've got that in abundance.
"It needs to keep growing, and it will do - with the new players coming in and the players that will join in the next week or two. That's driven and player-led. We set the temperature of the greenhouse and off they go. They're growing."
Wilder is interested in Southampton's Sam Gallagher and Scott Hogan, of Aston Villa, while reports suggest he is monitoring Leeds United's Kemar Roofe.
"It is important that we ramp up the schedule and we have done," Wilder added.
"The lads want to do their best in every session. We put a running session on on Tuesday, we've taken them out of their comfort zone and the lads have done their best.
"We've had four sessions on the grass in two days and overall the first two weeks of pre-season has been excellent. The lads have come back in good nick, we are recording times, the progress is measurable and it has improved from the first week.
"Our last two pre-season trips have set us up for the campaign and hopefully this will be the same."