PEORIA, Ariz. -- The Mariners sold more than 16,000 tickets on Thursday as fans reacted to the news that franchise icon Ken Griffey Jr. was returning to Seattle.

During the past two weeks prior to the announcement, the team had been averaging a little more than 1,000 tickets purchased per day.

The ticket categories included 16-game packages, full-season, half-season, weekend, All-Star Club and suites of 40 or more.

Several thousand Opening Day tickets were also sold to 16-game plan and partial season-ticket buyers. Opening Day is included with full-season tickets only. Partial season-ticket buyers overwhelmingly opted for the Opening Day additional tickets, according to a club official.

"We had a very busy day in the season-ticket sales department," a spokesperson said. "There was a steady stream of phone calls from the time the [telephone] lines opened at 8:30 a.m. [PT].

"There was also a huge spike in web activity, especially people clicking through to the season-ticket page."

A better indication of Griffey's impact on ticket sales could come next week, when six-game Flex Packs become available. A presale for Mariners mail subscribers and previous Flex Pack purchasers will be available at noon PT on Wednesday.

That package becomes available to the public on Friday at 10 a.m. PT.

The Flexible six-game ticket packages include Opening Day against the Angels as well as games against the Yankees, Red Sox and Giants. Fans choose three games from two categories with eight seating areas.

The tickets can only be purchased at Mariners.com/Flex.

Single-game tickets go on sale at 10 a.m. PT on March 14. The Mariners' home opener is on April 14 against the reigning AL West champion Angels.