Yes, in principle.
There are good and not so good elements to the plan. Starting with the good. Preservation of the playing field is to be credited, as is the preservation of the allotments. Loss of either would be problematic on health and community grounds. It is also to be credited that there would be habitat improvements made to potentially both a grassland and wetland habitat.
That taken into account, there are issues with other elements. Single points of access are problematic for emergency services and due to potential disruption for residents in the area if any works are done to the access road. They also preclude public transport provision, though on a site of this scale it should not be detrimental in this regard. A second point of access, if feasible, would be desirable to overcome the primary issues of concern though.
However, the existing access road would appear to intersect the grassland habitat. Roads are one of the most disruptive elements to habitats. It cannot be ignored that this would severely disrupt the performance of the habitat. That is not to say irreconcilably. Plans would have to demonstrate how this is achieved as they emerge and go through the planning process.