Villa have struggled since their talisman was injured in February and have slipped into the bottom half of the Premier League table and Smith thinks the club must invest wisely in the transfer market to ease the burden on Grealish.
He said: "We are always looking for that, we know we have an exceptional talent on our hands and any team he came out of would be weaker for it. We have to make sure we are looking to improve as a squad next season.
"We looked at it when we got promoted and we had to build a squad from scratch pretty much. We bought in 13 new faces, five this season and we have to add to that squad to keep improving.
"That's what you have to do to be a force in the Premier League. Next year will be our third season in the Premier League, you are playing catch-up with the bigger clubs and the finances they have had has enabled them to be stronger.
"We have been planning for this window since the last window closed and probably before that. We have our plans and they will continue to evolve."
Smith admits that Villa are being "tentative" with regards to Grealish's comeback after the midfielder suffered a setback after his previous attempt at recovering from injury.
He said: "Jack's scan came back positive so we are gradually starting to load him this week. We are a bit tentative with what happened last time."