The All England Lawn Tennis Club plans to invest in grass court tournaments in Europe to help players prepare for the Wimbledon championships in 2020.
The plan includes investments in new grass courts in Stuttgart and Mallorca, with the AELTC set to become the owner, rights or licence holder of four new tournaments through collaborations.
"A strong and successful grass court season is absolutely critical to the future of grass court tennis and thus the future success of the (Wimbledon) championships," a statement from AELTC chairman Philip Brook read.
"Having worked to expand the grass court season to be a meaningful gap between Roland Garros and Wimbledon, we're pleased to be making these significant further investments into ensuring that quality grass court tournaments can be provided at all levels of the professional game."
The French Open next year ends on 7 June, with Wimbledon set to begin three weeks later on 29 June.
While the first week of the grass court swing remains unchanged, with events in Nottingham (WTA), Hertogenbosh (ATP and WTA) and Stuttgart (ATP), the second week will feature a new WTA event in Berlin.
London and Halle will continue to host ATP events in the second week.
An ATP 250 event in Mallorca will be added to the calendar in the third week, while Bad Homburg is set to host a new WTA event, which is subject to approval, with events in Antalya and Istanbul being replaced.
The Mallorca championships will be held from 20-27 June next year with a €900,000 prize fund.
"Spain remains a key market for the ATP Tour and we are delighted to see the return of an ATP 250 tournament to Mallorca," ATP executive chairman and president Chris Kermode said.
"Bringing a grass court tournament to Spain is an exciting development in the ATP Tour calendar and we'd like to thank the AELTC for their continued investment in the grass court season."
It will be the first time an ATP event has been held in Mallorca for 18 years.
"I'm very proud that there will be an ATP tournament in Mallorca after so many years again," tournament director Toni Nadal said.
"After four successful women's tournaments, we are now starting a new, exciting tennis era in Mallorca with this men's event."