Grafton Street, the four-year-old upscale bar and grille may evade the looming threat of leaving Harvard Square by moving to the 1 Bow Street building that previously housed the storied Bow and Arrow Pub, owner Patrick Lee said yesterday.

"We're concentrating all our efforts on this location," Lee said.

Lee announced last June that the restaurant would be forced to vacate its prime location at 1280 Mass. Ave to make room for the expansion of neighboring Cambridgeport Bank.

The Bow and the adjacent Dunkin' Donuts and Baskin Robbins franchise closed last May, squeezed out by soaring Square rents.

In an effort to remain in the Square, Lee has been negotiating for weeks with the management company of 1 Bow Street, IDM Inc.

"We have had discussions, but we've signed nothing," said IDM Project Manager Warren Healer.

Lee said the Bow and Arrow spot is quite attractive.

"It's not too far from the original restaurant," he said. "In fact, it's a situation where we almost would have a little more visibility, especially with clients coming in from Boston."

"Most importantly, it's not too far of a stretch for our current client base," he added.

However, Lee said that the time frame could pose a problem.

Grafton might be forced to leave its current location as early as February to make way for the bank's expansion. Lee said he is not sure when the restaurant might be able to move into the Bow Street space.

A successful move requires a "seamless transition," Lee said.

Lee said he is currently working to negotiate a short-term lease with the building's owner, the T.H. Niles Real Estate Group, to allow the restaurant to remain in its current location until May.

If Grafton is forced to shut its doors too long before it can move into the 1 Bow Street building, it may never reopen, Lee said.

"We need one store to close and then the next to open down the street without any time in between," Lee said. "If there is a shutdown for a long period of time, the move simply may no longer be possible from a monetary standpoint."

But IDM may not finalize the new tenants until the beginning of January, Healer said.

The building's development process has been the main focus of IDM's discussions, Healer said.

"We recently decided that we are going to have three tenants on the ground floor, rather than one large tenant to occupy the entire building" Healer said. "Who those tenants will be, we just don't know yet."

At a bustling Grafton Street early yesterday evening, customers say they were pleased to hear that the restaurant has a hope of remaining in the Square.

"I come here about once a month, and I'd just hate to see it disappear," said Anselm Snodgrass of Gardner Street, Cambridge, as left the restaurant yesterday evening.