Okay. . .the Vikes' pre-season opener against the Raiders IS a national game, and will be televised at 7 pm Central time on ESPN. As far as the other 3 pre-season games are concerned, here's the schedule.
Vikings at Pittsburgh
Game Played - 19 August (Saturday), 7 pm Central
Game Shown on NFL Network - 20 August (Sunday), 4 pm Central
Baltimore at Vikings
Game Played - 25 August (Friday), 7 pm Central
Game Shown on NFL Network - 26 August (Saturday), 9 am Central
Vikings at Dallas
Game Played - 31 August (Thursday), 7 pm Central
Game Shown on NFL Network - 1 September (Friday), 12:00 noon Central
Also, interestingly enough, the play-by-play of the games on the NFL Network will be split between the two announce teams. The first half of the game will be called by the home team's announce crew, and the second half will be called by the road team announce crew. For example, when we play Baltimore, we'll get to hear the Vikings' play-by-play folks announce the first half of the game, and the Ravens' play-by-play crew doing the second half.
By God, football is almost here!