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Beginning on Friday, the San Diego Padres and the St. Louis Cardinals will clash in a three-game set that will provide clarity in the National League wild card race. The Cardinals entered Thursday with a one-game lead over the Padres, as well as a 1 1/2 game lead over the Cincinnati Reds. (The Cardinals are off Thursday while the Reds and Padres finish their business elsewhere, meaning those gaps will change.) Depending on how things play out over the coming days, either the Cardinals or Padres could find themselves in the catbird seat for a trip to the postseason.

With that in mind, let's set the scene by previewing the matchup ahead of Friday's series opener, beginning with the essentials.

The essentials

Friday: Vince Velasquez (SD) vs. Miles Mikolas (STL) | 8:20 p.m. ET

Saturday: Yu Darvish (SD) vs. J.A. Happ (STL) | 7:15 p.m. ET

Sunday: Jake Arrieta (SD) vs. Adam Wainwright (STL) | 2:15 p.m. ET

The starting pitching matchups would appear to favor the Cardinals. Friday's game will mark Velasquez's first appearance with the Padres, whom he joined on Wednesday after being released by the Philadelphia Phillies. Mikolas has had a miserable season because of injury and poor performance, so there's a fair chance that the series opener turns into an offensive display for both sides.

On paper, at least, Saturday's game would seem to be the most likely to be a pitcher's duel. Happ has performed much better than anyone would've expected when the Cardinals acquired him at the deadline. In eight starts since, he's compiled a 4.08 ERA (95 ERA+) and a 2.50 strikeout-to-walk ratio. Darvish, for his part, has experienced some rough sledding as of late. Since August 1, he's accumulated a 7.94 ERA in six starts while averaging just under five innings per pop.

The Cardinals should have a distinct advantage on Sunday. Wainwright is in the midst of a splendid season. Arrieta is very much not. He's surrendered 11 runs in 12 innings since joining the San Diego rotation last month.

Teams heading in opposite directions

It wasn't long ago that the Padres and Cardinals' playoff fates seemed unlikely to intertwine. 

On July 13, or the day of the All-Star Game, the Padres had the fourth best record in the National League, at 53-40; the Cardinals were 44-46, or closer in the loss column to the Miami Marlins than the Padres. Since then, the Cardinals have tied for the fourth best mark in the NL, going 32-23. The Padres, conversely, have gone 22-30.

The Cardinals will enter Friday having won five consecutive games, the second longest active winning streak in the majors. The Padres, for their part, are 9-21 over their last 30.

Predictably, SportsLine's forecasts are more favorable to the Cardinals' playoff chances. SportsLine has St. Louis with a 49.3 percent shot at making it to October, as opposed to just a 13 percent mark for San Diego. The Reds, by the way, are at 29.3 percent, meaning the Padres are the darkhorse of the trio.

Goldschmidt on fire

If there's one player to keep an eye on this series, it's St. Louis first baseman Paul Goldschmidt. He's no stranger to the Padres, having  spent his first eight seasons in the NL West with the Arizona Diamondbacks. It was largely during that time that he amassed a career .300/.416/.524 slash line against the Friars.

Goldschmidt has been one of the best hitters in the majors as of late. He's hitting .343/.427/.696 with eight home runs in the last 30 days. His 196 wRC+ (a FanGraphs metric that adjusts for ballpark, among other variables) is the fourth-best in the majors among qualifying hitters, behind only Bryce Harper, Ian Happ, and Javier Báez.

If Goldschmidt can stay hot, the Cardinals just might exit this weekend with a sizable lead over the Padres.