⚾ Pirates vs. Cardinals Prediction & Picks: MLB Odds for Thursday, May 21

Fresh off their first victory of the season against the St. Louis Cardinals, the Pittsburgh Pirates now look for their first series win against their division rivals, with first pitch scheduled for 1:15 p.m. ET (ESPN Unlimited). Braxton Ashcraft toes the rubber for Pittsburgh and is opposed by St. Louis righty Dustin May, with the Pirates listed as -130 betting favorites.

My Pirates vs. Cardinals prediction believes Ashcraft will lead the road favorites to victory after bouncing back from what was his worst start of the season the first time he faced St. Louis. That begins with limiting one of the Cardinals’ biggest power threats in Jordan Walker, and I also expect a Pirates slugger to go deep and do his part with providing run support with the last of my MLB picks.

⚾ Pirates vs. Cardinals picks & odds today

See all of our experts’ MLB picks based on the latest MLB odds; picks rated on a 1-to-5 star confidence scale based on betting value.

Total wagered: 2.25 units | Max profit: 2.81 units

🏆 Who will win Pirates vs. Cardinals?

St. Louis has an expected win/loss record four games worse than what its actual record is, and I expect that regression to start to take place in today’s series finale with Pittsburgh being victorious.

Score prediction: Pirates 5, Cardinals 3

💰 Pirates vs. Cardinals prediction & best bet

Pirates ML (-126)

Much of the reason St. Louis has a 24-23 expected win/loss record compared to its actual 28-19 record is what is perceived to be an unsustainable 10-3 record in one-run games, and 7-1 record in extra innings.

Entering this series, the Cardinals were tied for 11th in run differential, 11th in runs per game, third in defensive runs saved and first in the percentage of extra bases taken. And while they were 10th in starting pitching ERA (3.88), their expected ERA ranked 27th (5.09), and had other worrisome metrics like a 22nd-ranked bullpen ERA.

🔥 Best Pirates vs. Cardinals player prop bet

Jordan Walker Under 1.5 total bases (-157)

In the first game Braxton Ashcraft pitched against St. Louis this year, Jordan Walker had a multi-hit game, but only singled, struck out, and hit a sacrifice fly in three at-bats against the righty.

Ashcraft has been tough on right-handed batters, allowing a .209/.237/.286 slash line with five of the 19 hits off him going for extra bases.

While Ashcraft’s worst start of the season came against the Cardinals (six earned runs in 4 1/3 innings), he did record seven of his 13 outs via strikeout. He is also a big reason Pittsburgh’s starting rotation has the third-lowest FIP and eighth-best ERA.

💣 Pirates vs. Cardinals home run prediction

Oneil Cruz to hit a home run (+550)

Pittsburgh’s offense is vastly improved after finishing dead-last in home runs and runs per game a season ago. Cruz is one of four starters with an OPS at least 83 points higher than last season. And he in particular does not show signs of slowing down from a home run perspective, especially since he ranks fourth among all players in fastest bat speed (min. 150 swings).

Cruz is 1-for-3 with a home run off of Dustin May. The righty should show signs of regression, as his HR/9 rate was 1.4 in each of the two previous seasons where he made 10-plus starts. In addition, his 52.3% hard-hit rate allowed is on pace to obliterate his previous career high of 44.6%.

🚀 Pirates vs. Cardinals same-game parlay

All three legs of this same-game parlay work well together to help Pittsburgh's chances of securing an outright win. Instead of backing Cruz to hit a home run, I'm swapping out that wager for him to stuff the stat sheet in other ways with the third leg of this parlay, with the idea being that the entire Pirates lineup should find success against May's eighth percentile whiff rate and third percentile hard-hit rate. 

💵 My betting record for MLB picks

All MLB picks, including SGPs, have been tracked since March 26.

💡 How I'm betting Pirates vs. Cardinals: MLB strategy

Follow all of our MLB analysis and expert predictions for baseball season.

Since I expect a solid outing from Ashcraft having a big part in Pittsburgh winning this series finale, I wouldn't put anyone off backing the Under 3.5 runs on the Cardinals team total. Though I also toyed with the idea of backing the full-game Under, I didn't trust May's ability to match zeros as much, and am actually getting more value with the 55.75% implied odds for a Pirates victory.

📊 Live Pirates vs. Cardinals odds

Despite St. Louis having gotten the slight 55% majority of early wagers as underdogs, Pittsburgh's odds have moved as much as 10 cents from an opening number of -125 to -135 at BetMGM. That reverse line movement suggests sharps are backing the road favorites. 

The total has a much more lopsided betting split (71/29 in favor of the Over), which is why the O/U has fluctuated a ton between 7.5 and 8. Depending on which side of the total you are on, you can likely shop for the more favorable number, as the line should continue to fluctuate between the two totals before first pitch.

📈 Pirates vs. Cardinals betting trends

🚑 Pirates vs. Cardinals injuries

📺 How to watch Pirates vs. Cardinals

• Date: Thursday, May 21
• First pitch: 1:15 p.m. ET
• Ballpark: Busch Stadium (St. Louis)
• TV: ESPN Unlimited
• Streaming: MLB.TV
• Pirates starter: Braxton Ashcraft (2-2, 3.09 ERA)
• Cardinals starter: Dustin May (3-4, 4.81 ERA)