Prediction, Preview, and Odds
#2929 Arizona Diamondbacks vs.
#2930 Houston Astros
Saturday, September 18, 2021 at 7:10pm EDT
Written by Nick Raffoul

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The Arizona Diamondbacks will continue their interleague series battle at Minute Maid Park against the Houston Astros on Saturday night.

Houston is cruising towards October after building a commanding seven-game lead in the American League West race. Meanwhile, the Astros are trying to salvage what’s left of a 47-99 season.

Can the Astros take care of business at home against the lowly Diamondbacks on Saturday?

Castellnos getting extended look in DBacks rotation

Arizona will hand the ball to right-hander Humberto Castellanos at Minute Maid Park on Saturday. The 23-year-old debut in the bullpen but has earned an extended look in the starting rotation during the month of September. Castellanos enters with a 2-1 overall record to go along with a 3.90 ERA in 11 games (four starts) this season. In his previous trip to the mound, the rookie surrendered three hits in 5 ⅓ frames to beat the Seattle Mariners.

Castellanos earned a call-up earlier this season by going 6-1 with a 4.99 ERA in 12 Triple-A starts. Despite his ERA, he posted encouraging peripherals at the minor league level, fanning 9.21 batters and walking just 2.18 batters per nine innings of work. However, those rates haven’t quite translated to the big leagues just yet. Through 30 innings, Castellanos owns a 6.30 K/9 strikeout rate and 3.30 BB/9 walk rate.

This will be Castellanos’ first career appearance versus the Astros.

McCullers Jr. seeks third straight quality start

Houston is scheduled to counter with right-hander Lance Mcculler Jr. for the second game of its series against Arizona on Saturday. In 25 starts, McCullers is 12-4 with a sparkling 3.12 ERA and he’s turned into a reliable innings-eater for the Astros, pitching into the sixth inning or more in five of his last six starts. The 27-year-old has turned in back-to-back quality starts against the Seattle Mariners and Los Angeles Angels. Last time out, he limited the Halos to just one run on three hits over six frames to escape with the win.

While he’s had some trouble with free passes this season, McCullers Jr. has fared well on the mound in 2021. He has struck out a healthy 10.48 batters per nine innings of work, the second-highest rate of his career. The Astros’ right-hander has also found a way to tight up with runners on base, stranding 80.1 percent of his base runners so far this year.

In three career starts against Arizona, McCullers Jr. comes in with a 1-1 record and an 8.56 ERA. According to Baseball Savant, current Diamondbacks are batting .262 in 48 plate appearances off of the Astros’ right-hander heading into Saturday’s contest.

Best Bets for this Game

Full-Game Side Bet

Insiders Status:


McCullers has been trending up heading into the postseason but he's still out-pitched his peripherals to this point in this season. He is currently walking batters at the second-highest rate of his career and has benefited from a high strand rate in 2021. Meanwhile, Castellanos has flashed encouraging signs as a starter, which should leave some value on the DBacks at this price. Take Arizona to come out on top on Saturday.

Prediction: Arizona Diamondbacks +230

Full-Game Total Pick

Insiders Status:


These two teams are projected for nine runs but that number might be hard to come by here. Castellanos has allowed more than three earned runs just one time in 11 appearances (four starts) this season. Meanwhile, McCullers Jr. has also been tough to score on, giving up two earned runs or fewer in six of his previous eight outings. Look for this game to stay under the projected total at Minute Maid Park on Saturday.

Prediction: Under 9

Written By Nick Raffoul , "Nick Raffoul"

Shortly after graduating with an Honors in Business Administration, Nick turned his attention from traditional stocks and bonds to investing in the performance of sports teams. He has been a very successful sports bettor over the years and has now brought his talents to us here at Winners & Whiners. Nick uses a combination of advanced stats and historical data to create sports investment models to identify value and generate consistent profits. Let Nick win for you.