United have reportedly been keen on the forward ever since Red Devils boss Sir Alex Ferguson sent his brother and scout, Martin, to assess the forward.
Nihat has had a superb season for title-chasing Sociedad, and it is no secret that Ferguson is contemplating bringing in a forward to Old Trafford in the summer.
Astiazaran has reinforced this by claiming United have made an approach.
"There are some offers for Nihat," Astiazaran told the Turkish press. "But Manchester United's offer is the most serious.
"If Nihat want to play for Manchester United, this transfer can become fact."
Nihat`s pace and eye for goal would make him a perfect foil for Ruud van Nistelrooy.
Van Nistelrooy`s goals have kept United challenging for honours both domestically and in Europe, but Ferguson would dearly love to take some of the burden from the Dutchman`s shoulders.
A price of ‚é¼10 million has been mentioned, which would certainly be within budget for the Old Trafford titans.
Nihat has a contract with the San Sebastian outfit that runs until 2006, but would surely be tempted by a move to Manchester.
