It's early April and if my memory serves me well several of the weekday day games this early in the season cater to a lot of youth groups. Whether the Tigers give away the tickets or sell them at a discounted price.
Given there was quite a bit of chatter on this board Wednesday evening about the possibility of the game being postponed and the forecast's likelyhood of rain in the forecast, the powers that be decided they would be better off calling the game rather than have a couple thousand youngsters in the stands, or halfway to the ballpark and then call the game.
It allowed the groups, schools or whatever to reschedule their plans, possibly use a cancelation clause with their transportation providers. The kids and chaperones still get a ticket to a future event.
It also saves the team from criticism and grief from parents whose kids may of had to sit thru possible delays. As opposed to criticism from a couple moron message board posters.