The Metropolitan Transportation Authority and Tishman Speyer missed the first deadline under their tentative agreement to develop the West Side rail yards, a deal reached two weeks ago.

Yesterday was the deadline for the MTA to officially designate Tishman Speyer as the developer of the 26 acres that constitute the Hudson Rail Yards, which was part of an agreement approved by the MTA board late last month.

The MTA did not issue a “conditional designation letter” to Tishman Speyer yesterday, but representatives of both sides said an agreement is likely imminent. “An agreement is currently being negotiated with the MTA and we expect to conclude those negotiations soon,” a Tishman Speyer spokeswoman, Virginia Lam, said in a statement.

“We expect to reach an agreement in the very near future,” a spokesman for the MTA, Jeremy Soffin, said.

Tishman Speyer’s winning bid was valued at $1.004 billion.

The other bidders were Extell Development Co., the Related Cos., Brookfield Properties, and a joint venture of the Durst Organization and Vornado Realty Trust.

Tishman Speyer now has tentative approval from the MTA for a 99-year lease, but the western portion of the rail yards requires a rezoning and will have to go through the city’s land use review process before ultimately getting approval from the City Council, which could delay construction there for years.