Cubs vs. Pirates Prediction, Odds & Expert Picks: MLB Best Bets for Sept. 15

Our Cubs vs. Pirates prediction expects the visitors to win outright following a change to Pittsburgh's pitching plans.

Mike Spector

Last Updated: September 15, 2025 11:02 AM EDT • 6 minute read

Cubs vs. Pirates Prediction, Odds & Expert Picks: MLB Best Bets for Sept. 15 — Pictured: Chicago Cubs starting pitcher Jameson Taillon throws a pitch. Photo by Jonathan Hui-Imagn Images

The Pittsburgh Pirates made a pitching change late Sunday, moving ace Paul Skenes’ start against the Chicago Cubs to tomorrow, and I break down how that changes the outlook for this series opener with my Cubs vs. Pirates prediction as part of our MLB picks. First pitch from PNC Park in Pittsburgh is scheduled for 6:40 p.m. ET (MLBN).

Chicago is a -135 moneyline betting favorite, and while the Cubs also changed their starting pitcher from Cade Horton to Jameson Taillon, the market did not adjust enough in my opinion for the changes in who is toeing the rubber. That leaves Chicago as the rightful favorite at a great price.

You won’t find any batters in this game as part of my best home run predictions today, but I am still high on a Cubs batter’s player prop.

⚾ Cubs vs. Pirates prediction

MLB expert picks made Monday; odds subject to change.

Moneyline pick: Cubs (-130 via FanDuel) ⭐⭐⭐⭐
Run line pick: Cubs -1.5 (+130 via Caesars) ⭐⭐⭐
Over/Under pick: Under 8.5 (-120 via FanDuel) ⭐⭐⭐

📝 Cubs vs. Pirates preview & best bet

Track the latest MLB scores for line movement and matchup info.

🐻 Cubs ML (-130) ⭐⭐⭐⭐

The Pirates have allowed four or fewer runs each of the last six times the newly named starter, Braxton Ashcraft, has toed the rubber. But the light-hitting home underdogs cannot be trusted to score enough runs to win this game outright, which is why I am backing Chicago with my Cubs vs. Pirates best bet.

Ashcraft has been used out of the bullpen more recently to serve as a long reliever piggybacking off Mike Burrows’ starts. He has only pitched into the sixth inning once this year, while 19 of his appearances have been three innings or shorter. That will continue to put stress on a bullpen that has worked more of late, especially since the team is being cautious about Skenes’ innings as well.

The Cubs have received production from up and down their lineup of late. Moises Ballesteros, MLB.com’s 50th-ranked prospect, is batting .321 with three extra-base hits and eight RBI through his first nine big-league games. Meanwhile, Ian Happ ensured us a profitable day with yesterday’s home run, which makes six home runs over his last 14 games.

FanDuel is the only one of our best sports betting sites where you can back the Cubs at -130 odds. All other competitors are at least at -135, which carries a 57.45% implied probability that the road favorites will win outright. At -130 odds, a $10 winning wager would net $7.69 in profits.

💰 Best Cubs vs. Pirates player prop bet

Our MLB player prop odds tool shows the best odds for every market across legal sportsbooks in your area.

⬆️ Ian Happ Over 0.5 RBIs (+213) ⭐⭐⭐⭐

The change from Skenes to Ashcraft significantly improves the odds of Cubs hitters’ player props, and I have identified one of Ian Happ’s props that would pay out $21.30 in profits on a winning $10 wager as my best Cubs vs. Pirates player prop bet.

Happ has a 20.6% barrel percentage over his last 14 games, along with a 58.8% hard-hit percentage, and an average exit velocity of 107.2 mph.

Sixteen of Happ’s 21 home runs have also come against right-handed pitching. While I am not backing Happ’s best +760 home run odds at DraftKings, the fact that Ashcraft has allowed a 0.31 HR/9 rate and 4.3% HR/FB rate to left-handed batters in 58 1/3 innings pitched suggests the righties are going to have to do much of the damage offensively in this game.

Happ has a 31.95% implied probability to drive in a run for the third time in the last four games, which is a great value for someone as hot as he has been over the last two weeks.

📊 Cubs vs. Pirates odds: Sept. 15

MLB odds update live in real time.

📈 Cubs vs. Pirates betting odds analysis

With the relatively new news about both teams changing their starting pitching plans for today, the odds have not had much time to move off the opening -135 moneyline odds. I expect the line to move in Chicago’s favor once more bettors catch wind that Skenes is now slated to pitch tomorrow.

FanDuel was the only best sports betting app that moved to an O/U of 8.5 runs off an opening number of 8.0, but it has since aligned with the rest of the market while keeping its juice at -122 to the Over and +100 to the Under.

🔢 Cubs vs. Pirates stats

Season stats courtesy of baseball-reference.com.

Cubs (85-64)	Statistic (per game)	Pirates (65-85)
4.89	Runs	3.60
8.43	Hits	7.68
.248	AVG	.232
.426	SLG	.349
.746	OPS	.654
3.81	ERA	3.79
7.66	K/9	7.99
2.52	BB/9	2.93
1.23	HR/9	0.94

🚑 Cubs vs. Pirates injuries

📺 Cubs vs. Pirates game info

When: Monday, Sept. 15
First pitch: 6:40 p.m. ET
Where: PNC Park (Pittsburgh)
How to watch: MLB Network

💡 Expert MLB predictions today

❓ Cubs vs. Pirates FAQs

Who is favored to win Cubs vs. Pirates?

The Cubs are the -135 betting favorite to beat the Pirates on the road on Monday.

What is the run line for Cubs vs. Pirates?

Chicago’s -1.5 odds range from -146 to -156, while Pittsburgh’s +1.5 odds are at +130 on the high end of the market.

What is the Over/Under for Cubs vs. Pirates?

The O/U is at 8.0 runs across the market, and it’s juiced to -115 for the Over and -105 for the Under.

What are the best bets for Cubs vs. Pirates?

My Cubs vs. Pirates best bets back Chicago to win outright (-130) and for Ian Happ to go Over 0.5 RBI (+213).

When is the Cubs vs. Pirates game?

The Cubs vs. Pirates first pitch is set for 6:40 p.m. ET, airing on MLB Network.

How do baseball odds work?

When betting on MLB, the run line shows how many runs the favorite needs to win by in order to cash the bet. For example, a favorite of -1.5 must win by two or more runs to cover the run line, while an underdog at +1.5 must win outright or lose by one run to cover the run line.

Moneyline odds represent the payout for picking the outright winner (+200 means a $100 bet wins $200, while -200 means a $200 bet wins $100). Over/Unders let you wager on whether the combined total of runs will be higher or lower than the set number.

You can determine the payouts and implied probabilities for any wager - or convert odds to different formats - with our odds converter.

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Written by:
Mike Spector

Mike started in the sports writing industry in July 2019, and gained a lot of followers in his first year after finishing with the No. 2 overall record in an annual NFL betting competition, which made picks against the spread, and from an Over/Under and moneyline perspective. Mike is an avid fan of the NFL, MLB, tennis, and all college sports. In his opinion, March Madness is the best sporting event there is, and he's especially euphoric starting with conference tournament time in college basketball. Mike's a big advocate of "fading the public" and making plays that are contrarian, constantly citing that "there are reasons why they have those big shiny buildings in Las Vegas." When making wagers, Mike leans on his NFL experience and always scours the best odds at all of the major sports betting sites, where he mostly sifts through DraftKings, FanDuel, BetMGM, and bet365. He's tried several others and is of the firm belief that bettors should not just stick to one sportsbook, as there is always likely better value to be had with the same wager. In addition, while Mike received his undergraduate degree from Villanova University, he has no issue betting against the Wildcats when it comes to college basketball wagering, and suggests other bettors should always put their “head” before their “hearts.”