On Thursday, fans can start signing up for a chance at the toughest Phillies ticket - Opening Day.

So far, buying a full-season ticket plan has been the only way to get the first home game - Friday, April 5, against the Kansas City Royals - through the club.

It hasn't been available through partial-season ticket plans, or - at least so far - through Six Game Packs, which can include the ever-desirable Fireworks Nights and Red Sox games.

Also, when single-game tickets go on sale Feb. 13, Opening Day will be excluded, according to John Weber, vice president for sales and ticket operations.

Some tickets for the Red Sox games, May 29 and 30, will be available.

The system for getting Opening Day tickets works like a lottery, with names being chosen. But fans don't win tickets - they win the right to buy tickets.

[UPDATE: Here's a link to the Opening Day Ticket Opportunity at Phillies.com. The page spells out the rules and other details, including the sign-up deadline (Feb. 22), and how winners will be notified (email). The drawing date, however, has yet to be announced. Must be 18 years old to enter.]

Those who miss out may still have a couple of other chances, without resorting to the ticket resellers like StubHub.

It's possible Opening Day may later be added to the mix of Six Game Packs, Weber said.

Also, in prior years, the Phillies have reserved 500 standing-room tickets to be sold two or four hours before each game at Citzens Bank Park. (Last season's schedule was 9 a.m. for early afternoon games, noon for 4:05 p.m. games, 4 p.m. for evening games.)

Contact staff writer Peter Mucha at 215-854-4342 or pmucha@phillynews.com.