NEW YORK (AP)  The NFL players’ union has told the league not to begin collecting blood samples for HGH testing yet.

“We informed the NFL (Tuesday) that absent a collective agreement on several critical issues, blood collection is not ready to be implemented on Monday,” the NFL Players Association says in a statement released Wednesday. “We have advised the players.”

The league was preparing to draw the blood samples beginning Monday, although full testing for HGH was not yet scheduled.

The new CBA includes a clause allowing the NFL to become the first major U.S. professional sports league to test for HGH, but the players have balked, saying they don’t have enough information to feel comfortable with testing procedures.

(Copyright 2011 by The Associated Press. All Rights Reserved.)