City council has rejected a motion to designate a University of Toronto natural-grass field as a "cultural heritage landscape," paving the way for a $9.5-million plan to install artificial turf there in the lead-up to the 2015 Pan Am Games.

The grassy area at the university's back campus, near Hart House,  will be used for field hockey events when Toronto hosts the Games.

The prospect of losing the green space to a synthetic pitch upset some preservation advocates who viewed the storied field through a nostalgic lens. The university was scheduled to break ground on the project beginning next month, but Coun. Adam Vaughan spearheaded a last-ditch effort to keep the surface natural, introducing a motion late last month to protect the field as a heritage site.

After council turned down the proposal on Wednesday, a disappointed Vaughan told reporters the loss is much more than just about a sports field, but about losing a common ground.

Relocating field could cost $13M

"Frosh activities take place here, concerts take place here, there are picnics, there are all kinds of events that take place here," he said. "Now only field hockey events can take place here."

Concerned citizens such as author Margaret Atwood and academics from the university's forestry, architecture and history departments had weighed in, arguing in favour of preservation of a natural environment.

However, supporters of the artificial turf scheme noted that the project was known to the public as far back as 2009, and that it would be late at this point to scramble for a back-up plan if the motion were to pass.

Scott Mabury, U of T's vice-president of university operations, had estimated that relocating the field could cost as much as $13 million. He said the university was "blindsided" by what he characterized as an 11th-hour move steered by Vaughan.