Two more weeks could pass before the Minnesota Sports Facilities Authority receives construction cost estimates for the proposed $975 million Vikings stadium, chairwoman Michelle Kelm-Helgen told legislators Thursday.

"Coming to these numbers has been a little more difficult than we had originally anticipated, and it certainly is taking more time," Kelm-Helgen told members of the Legislative Commission on Minnesota Sports Facilities. The estimate could arrive within two weeks, she said. Groundbreaking will take place soon afterward.

Even the lowest proposed bids from subcontractors have been higher than expected, she said slowing the arrival of the "guaranteed maximum price" from Mortenson Construction, the stadium's construction manager. In the meantime, the commission is trying to stretch their dollars, focusing on cheaper, "relatively minor" design changes in areas such as paint or materials on smaller fixtures. However, there will be no "value engineering" of the major aspects of the stadium, such as its massive pivoting glass doors or cathedral-like glass roof, she said.

Despite the delay, Kelm-Helgen said the Commission is on track for the stadium's July 2016 opening and vows to stay within budget.

Thursday also marked the closing of a $17.1 million land deal for an adjacent plaza that's home to the Downtown East light rail station that will provide a vital link between the stadium and a proposed $400 million development by Ryan Companies that includes a three-block park and office space. The development will be crucial for sealing opportunities to host major events like the Super Bowl, Final Four and college football National Championship.

The purchase hit a snag last month when the owners, Minneapolis Venture LLC, filed suit against the authority claiming negotiations over the land purchase had grown "perplexing and unproductive." The company wanted $24 to 26 million for the property. They reached a deal last month.

Vikings Vice President of Public Affairs Lester Bagley told the Commission that they're "very close" to beginning construction, and that "groundbreaking is just around the corner" once the budget is in line.