By putting Ackley on the 40-man roster, his time of service in the Major Leagues begins immediately, and he also will be invited to Spring Training with the big league team next spring.
Zduriencik would not put a timetable for the sweet-swinging outfielder to reach the Major Leagues.
Ackley was the second overall selection in the Draft and becomes the highest-paid first-round choice in franchise history.
"When we selected Dustin, we knew he was a special player and a special person," Zduriencik said. "We are excited for him to join or organization and can't wait to see him in a Mariners uniform."
That could come as early as later this week, when the left-handed outfielder reports to Peoria, Ariz., to begin his professional career.
The Mariners also announced the signing of fifth-round Draft choice Tyler Blandford, a right-handed pitcher from Oklahoma State University. As a result of the latest two signings, Seattle came to terms with its top 15 Draft choices and 35 of the 52 selections overall.
But Ackley was the big catch.
"We think this is a player who will bat in the middle of our lineup in years to come," Zduriencik said. "He has put up terrific numbers at the college level."
Ackley became the first three-time All-American in University of North Carolina history. He earned first-team honors from Baseball America, Collegiate Baseball, the National Collegiate Baseball Writers Association, American Baseball Coaches Association and Rivals.com this past season; was among the five finalists for the 2009 Golden Spikes Award -- presented annually to the College Baseball Player of the Year; and was selected as the Rivals.com National Player of the Year.
The left-handed hitter was at his best in the postseason, becoming the first first player in the history of the College World Series to be named to the event's All-Tournament Team three times (2007, '08 and '09) and set the CWS career record with 28 hits (in 15 games). He ended his career with a 22-game NCAA Tournament hitting streak, going 50-for-99 (.505). Ackley batted .410 (55-for-134) in 31 career postseason games.
"He is very athletic, a left-handed hitter who will play nice in this ballpark," Zduriencik added, referring to Safeco Field. "He's the type of guy you look for who has plate discipline, and we're very excited about this sign."
Zduriencik lauded Minor League scouting director Tom McNamara and his staff for selecting and signing the class of '09, which could provide another big piece of the puzzle in getting the Mariners back into playoff contention.
The final day of the process was hectic. If Ackley and Blanford had not been signed by the deadline, they would have been eligible for the June 2010 Draft.
"There were many calls with [agent Scott Boras] throughout the week and the day," Zduriencik said. "We worked very hard on this one. It got down to the very end, and we're happy to have the young man on board."
Neither Boras nor Ackley were immediately available for comment.
While Boras was busy working with other clients, including No. 1 pick Stephen Strasburg, who signed with the Nationals, Zduriencik said the Mariners focused on getting Ackley under contract.
"There were a couple of times when we called Scott and he had to call us back, but it was very cordial throughout the day and throughout the process," Zduriencik said. "He represented his client in a first-class fashion."
The next step is "get him to Arizona as soon as possible," the Mariners' GM said. "We need go gauge where he's at. I imagine he will play in the Arizona Instructional League and have him participate in the Arizona Instructional League."
There are no definitive plans to have Ackley come to Seattle and work out with the team, but that could be discussed as early as Tuesday.
"Obviously, our first concern is to make sure we have everything taken care of baseball-wise," Zduriencik said. "Then we have discussions with him about maybe coming [to Seattle] for a press conference.
"But our focus tonight was getting his contract agreed upon."
Did he think this deal might not happen?
"I think there is always a possibility that a deal might not come together," he said. "But I think during the process we tried to stay very professional and tried to deal with this matter-of-fact. There is always a chance of not having a deal made, but in this case, I think we understood [Ackley's] desire to play and how good it was to be the second selection in the county and see what is happening in Seattle."
Zduriencik had mentioned several days ago that signing with the Mariners would be a good opportunity for any player.
"I think what you are going to see here, as we move forward, are the people that will be here are people with character, people with a desire to win and people who want to be part of something special, people that pull together as a team and respect each other," Zduriencik said. "I think this [season] is just the first steps in that direction.
"One of the things I said in the winter was that is a land of opportunity. You talk to the players in [the clubhouse] and ask them about the opportunity they've been given. They capitalized on it, and I tip my hat to a lot of these guys. We gave some of these guys the opportunity, and they've made the most of it."
Although it has been almost three months since Ackley played in the College World Series, Zduriencik didn't think the layoff was that much of an issue.
"He had a pretty long season and him coming off an injury [Tommy John elbow reconstruction surgery] probably wasn't a bad thing to take the summer to himself," Zduriencik said. "We'll speed his process up. We'll get him to Arizona and the Arizona Fall League and go from there."