Cubs vs Padres Wild Card Series Preview & Prediction: Who Will Advance to the NLDS?
Updated September 28, 2026
Updated September 28, 2026
The Chicago Cubs and San Diego Padres will meet for the second straight postseason, but the setting has flipped for this Wild Card series. The Padres earned the National League’s top Wild Card spot at 91-71 and will host the entire best-of-3 series at Petco Park, while the Cubs arrive as the No. 5 seed at 89-73. San Diego finished the regular season on an 8-2 run over its final 10 games, including a 9-4 win over Arizona on Sunday, while Chicago closed with a 6-2 win over Boston. The Cubs scored an MLB-best 850 runs, allowed 703 and finished with a +147 run differential, compared with San Diego’s +41. Will that matter more than San Diego's home-field advantage?
Why Our Model Sees Value:
“The Polymarket “Buy Yes” price for Chicago to reach the NLDS is 48¢. That price appears to give heavy weight to San Diego’s home-field advantage, recent form, and late-inning relief pitching advantage while giving too little credit to Chicago’s full-season defense and offensive ceiling.”
A Quiet Market So Far
The Polymarket price deserves extra caution because this particular NLDS qualification market has almost no trading activity on the Cubs and Padres outcomes. The displayed last-trade probabilities are less useful than the executable price, so 48¢ is the better figure to use for Chicago. At that entry point, my 52% series probability produces a 4% edge. I would still consider Chicago at 49¢ or 50¢, but above 50¢ the cushion becomes too small for a short series.
Advanced Metrics Favor Chicago
The Cubs’ 89-73 record came with a 95-67 expected record based on runs scored and allowed, while San Diego’s 91-71 record came with an 85-77 expected record. Chicago also won 5 of the 6 regular-season meetings and outscored the Padres 55-28, though the 23-3 Cubs win on July 1 inflates that margin. San Diego deserves credit for its late surge, its 51-30 home record and a bullpen built to protect narrow leads. Even after those adjustments, I make Chicago a small favorite because its lineup creates more ways to score, its defense saves runs at an extraordinary rate, and its overall run differential points to a stronger club than the standings alone show.
Recommended Position:
Cubs to Advance
Current Price:
48¢
Model Probability:
52%
Market Probability:
48%
Model Edge:
4%
Entry Threshold:
50¢
Model Confidence:
73/100
Chicago’s clearest advantage is run prevention once the ball is put in play. The Cubs finished with +70 Fielding Run Value and +72 Outs Above Average, both Statcast-era single-season records. Dansby Swanson and Nico Hoerner give Chicago premium range in the middle infield, while Pete Crow-Armstrong can erase extra-base hits in center.
That matters when making MLB predictions in a short series because San Diego has become far more dangerous offensively over the last month. The Padres were tied for the best wRC+ in baseball from the start of September, with Fernando Tatis Jr., Jackson Merrill and Ty France driving the improvement. Chicago cannot count on the version of San Diego that struggled to score in the first half. Its defense will need to convert borderline balls into outs and keep the Padres from extending innings.
The Cubs led MLB with 850 runs and finished third with 220 home runs. Crow-Armstrong completed a remarkable 45-homer, 41-steal season, and he enters October after posting an .894 OPS through 23 September games. Alex Bregman also returned at the right time. After suffering multiple fractures in his left cheek area, he came back as the designated hitter and went 4-for-4 with 2 home runs on Sunday.
San Diego’s offense is far better now than its full-season total of 722 runs suggests. Tatis hit 20 home runs after the All-Star break, France posted a .908 OPS in the second half, and Merrill has been one of the club’s hottest hitters late in the year. Manny Machado reached 30 home runs despite a less productive overall season by his standards. The Padres can score enough to win this series, but Chicago has more depth from the top through the lower third of the order.
Michael King is the one confirmed starter and gives San Diego the strongest individual starting arm in the series. He finished 12-10 with a 3.21 ERA over 185 innings. Nick Pivetta is the likely Game 2 choice after returning from a flexor strain and posting a 2.86 ERA in 8 starts. San Diego can then choose between Robbie Ray, who finished 13-8 with a 3.59 ERA, and Walker Buehler for a deciding game.
Chicago’s rotation is less settled. Matthew Boyd is the logical Game 1 choice on regular rest after allowing 1 run in 7 innings against Miami on September 24. Kevin Gausman remains a key variable because soreness in his non-throwing shoulder has left his status uncertain, although a Sunday bullpen session reportedly went well. Clay Holmes owns a 3.29 ERA, while David Peterson has been excellent recently with a 1.27 ERA over his last 4 outings. The Cubs have enough options, but San Diego has the cleaner Game 1 setup.
If the Padres lead after 6 innings, the game changes quickly. Mason Miller finished with 38 saves, a 1.67 ERA, and 129 strikeouts. Adrian Morejon added a 2.83 ERA with 107 strikeouts, and Bradgley Rodriguez posted a 2.19 ERA. San Diego’s relief group finished near the top of MLB and has the power arms to shorten games.
Chicago does not have the same late-inning certainty. Daniel Palencia has dealt with multiple injuries, Ryan Rolison has emerged as an important left-handed option and Ryan Zeferjahn gives manager Craig Counsell another right-handed arm for key spots. The Cubs may also use starters in relief because the Wild Card format allows aggressive pitcher deployment. Still, if Chicago repeatedly enters the seventh inning behind, our pick is in trouble.
Gausman is Chicago’s main pitching concern. His left shoulder soreness came from a diving tag play, not from throwing, but his availability could affect every pitching decision after Game 1. Bregman appears ready to hit after his facial injury, though Chicago may keep him at designated hitter rather than third base. Swanson recently returned from a left oblique injury and has been able to play.
San Diego will be without several pitchers, including Casey Mize, Lucas Giolito and Joe Musgrove. Jeremiah Estrada’s right shoulder impingement also removes an important relief option. Jason Adam has returned from a right shoulder strain, which helps restore some depth behind Morejon and Miller. Miguel Andujar has recovered from a right wrist fracture, though his Wild Card roster status remains uncertain.
San Diego has the home park, the hotter September record, the best confirmed starter, and the stronger late-inning pitching. Those are meaningful advantages in a best-of-3 series. Chicago, though, has the superior full-season run differential, the best defense in baseball, the league’s highest-scoring offense, and a 5-1 regular-season record against San Diego. The Cubs also closed the year with a 95-67 expected record based on runs scored and allowed, a much stronger mark than San Diego’s 85-77 figure.
That does not make Chicago a large favorite. It makes the current 48¢ qualification price attractive enough to take. My projection lands at 52% for the Cubs to reach the NLDS, with San Diego at 48%. My preferred position is Chicago to advance, with 50¢ as the highest entry I would accept.
