Southampton boss Ralph Hasenhuttl says his side must strengthen if they are to continue progressing.
The Saints have endured a difficult season, but had made a promising start to the campaign at one stage.
Hasenhuttl's side were top of the league in November, and in the top six after defeating Liverpool on January 4th.
Since, they have lost 12 of the past 15 league matches, and Hasenhuttl believes the lack of depth in the squad is the reason for their dip in form.
Asked about the link between the poor 2021 form and transfers, Hasenhuttl said, per the Daily Echo: "There is no question about that. We definitely step on the same spot all the time.
"We are not moving forward. There is no development like we wanted to see it.
"We had one very good term in this season where we over-performed with the way we played, but when you are not able to invest in changing the squad in the summer, you will end up again in the same position in the table.
"Then again it's a fight about staying in the league, because we tried everything to come to a different level. But as soon as we have not every player on the highest level, we have also not that depth in the squad to be then strong enough to put pressure on the guys that are not performing well.
"I think this is what we need next season."
