MLB Best Bets Tuesday | Picks & Predictions (5/21)

MLB Best Bets Tuesday | Picks & Predictions (5/21) article feature image

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There are 15 MLB games scheduled for Tuesday, May 21. Our staff of MLB experts has locked in on four MLB best bets, including moneyline and spread picks for Brewers vs Marlins, Padres vs Reds, Twins vs Nationals and Tigers vs Royals.

Continue reading below for our Tuesday MLB Best Bets.

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MLB Best Bets Tuesday | Picks & Predictions (5/21)

The team logos in the table below represent each of the matchups that our MLB betting staff is targeting from the Tuesday slate of games. Click on the team logos for any of the matchups below to navigate to a specific MLB bet discussed in this article.

GameTime (ET)Pick
7:40 p.m.
6:40 p.m.
6:40 p.m.
6:45 p.m.
Specific betting recommendations come from the sportsbook offering preferred odds as of writing. Always shop for the best price using our MLB Odds page, which automatically surfaces the best lines for every game.

Brewers vs. Marlins

Tuesday, May 21
6:40 p.m. ET
Brewers F5 ML (-135)

By Tanner McGrath

I’ll start here: this will be a lefty-on-lefty starting pitching matchup.

Over the past two weeks and against southpaws, the Brewers have posted the second-highest wRC+ among MLB lineups (150), while the Fish have posted the seventh-lowest (64). During that stretch, Milwaukee batters have pulled 31% of their batted balls with a 14% barrel rate, adding up to a ridiculous .353 expected wOBA. William Contreras is a stud, slashing .340/.407/.566 during the stretch with six walks to only 11 strikeouts.

Regarding left-handed starting pitchers, Milwaukee’s Robert Gasser is an interesting young arm. A by-product of the Josh Hader trade, Gasser boasts a dee five-pitch arsenal headlined by a sweeper with a 122 Stuff+ mark and 16 inches of glove-side break.

He struck out eight Cardinals in his MLB debut. Even if his second start wasn’t as dominant, he’s allowed only one earned run across his first 11 MLB innings.

The key for him is command and control, as he struggled with walks in the minors. But he checks in with a 98 Location+ mark so far, issuing only one free pass across his first two starts, which is good enough for me.

Conversely, Miami’s Trevor Rogers has lost a tick of velocity on his fastball, resulting in a 29-point year-over-year decrease in his fastball Stuff+ rating (from 89 to 60). Thus, he's heavily moderated the use of the heater and leaned into more secondary stuff, where he’s trying to nibble around the edges.

While he’s induced a few more chases, he's also significantly decreased his strikeout rate and increased his walk rate. After three consecutive seasons with a strikeout minus walk rate of around 16%, that mark is down to 9% this season.

He’s also getting walloped in the zone, allowing a 46% hard-hit rate that ranks in the 12th percentile among qualified starting pitchers.

Add it all together, and you get a pitcher with a 5.79 ERA and 5.10 expected ERA. He pitched well against the Tigers in his most recent outing, but the Brewers are a different beast.

I genuinely believe the Miami bullpen is an undervalued unit trending upward, so I’d rather avoid the latter innings and isolate the Gasser vs. Rogers lefty-on-lefty matchup by betting on the Brew Crew in the first half.

Pick: Brewers F5 ML (-135 | Play to -145)

Padres vs. Reds

Tuesday, May 21
6:40 p.m. ET
Reds ML (+102)

By Tanner McGrath

The Reds have a monstrous rest advantage on Tuesday.

The Padres are coming off a four-game weekend series against the Braves, with the final three coming in 24 hours after playing on Sunday Night Baseball and then ripping through a Monday double-header. They then traveled overnight from Atlanta to Cincinnati for this three-game set at Great American.

I’m worried that the bats will be slow. I’m concerned that the bullpen is extended – they used their four highest-leverage relievers on Monday.

Related, I’m super high on the Reds bullpen.

I don’t know if you’ve watched Fernando Cruz yet, but his splitter might be the best pitch in baseball. He’s throwing it nearly half the time, and hitters still can’t touch it, with 53 whiffs on 150 thrown. He’s struck out 36 of 84 batters faced (43%), and 31 have been put away on the splitter.

Pair him with Alexis Diaz, Brent Suter, and Emilio Pagan, and the Reds have a top-10 bullpen by fWAR (1.4) and strikeout minus walk rate (16%). They have a 28% strikeout rate and 3.05 SIERA over the past two weeks.

And, most importantly, they’re all rested because the Reds had an off day on Monday.

Padres starter Joe Musgrove finally pieced together his first excellent outing five days ago against this Reds lineup (6 IP, 2 ER, 4 H, 9 K, 0 BB).

However, I’m banking on the Reds flipping the script when facing the same pitcher for the second time in five days, especially considering Musgrove’s horrendous batted-ball profile.

Musgrove boasts an ERA and expected ERA above six. He’s allowing a career-high 11% barrel rate. His top three pitches have allowed an expected slugging over .500. His fastball velocity is down a tick, resulting in a three-point year-over-year decrease in his four-seam swinging-strike rate (from 17% to 14%).

Ultimately, after one good start, I’m not ready to buy Musgrove. And Cincinnati's added familiarity with Musgrove should produce better results.

As an aside, I think the Reds lineup is a tad undervalued despite the horrendous results. They've posted a reasonably low 41% ground-ball rate and a reasonably high 45% pull rate over the past two weeks, and you can be sure better days are ahead if you keep pulling the ball in the air.

Also, I’m ready to buy Andrew Abbott. His stuff numbers are bad, but the Stuff+ model doesn’t know how to quantify changeup-heavy southpaws accurately, and Abbott is leveraging his changeup into one of MLB’s best batted-ball profiles – he’s inducing a ton of weak contact, even if much of it is fly-ball contact.

As a result, Abbott’s expected ERA is below three.

And the Padres struggle against left-handed pitching, mainly because they don’t hit the side hard enough. They boast an 83 wRC+ and .611 OPS against the side over the past two weeks based upon a 39% pull rate and 28% hard-contact rate, both bottom-five marks.

So, this seems like a decent matchup for Abbott. That played out last July when the lefty put together his best start of the season at home against San Diego, striking out 12 across 7 ⅔ one-run frames.

Still, this is mostly a rest play. I’m betting the Padres are gassed and hope the Reds take advantage.

Pick: Reds ML (+102 | Play to +100)

Twins vs. Nationals

Tuesday, May 21
6:45 p.m. ET
Twins -1.5 (-110)

By Tony Sartori

We have again reached my favorite day of the week: Patrick Corbin Day.

The left-hander is slated to take the mound for Washington, and he comes into this contest with a 1-4 record, 5.59 ERA and 1.74 WHIP through nine starts.

His underlying metrics are even worse as Corbin ranks in the eighth percentile or lower among qualified pitchers in expected ERA, expected batting average allowed, and hard-hit rate allowed.

These woes should continue against Minnesota, a team he has faced just once over the past few seasons. In that outing, Corbin surrendered three runs on seven hits through six innings en route to a 3-1 loss.

Meanwhile, right-hander Joe Ryan is slated to get the ball for the Twins.

Ryan has a 3.57 ERA and 1.02 WHIP through nine starts this season. His underlying metrics are even better, ranking in the 86th percentile among qualified pitchers in expected ERA and 77th percentile in expected batting average allowed.

Not only does Minnesota possess the clear starting pitching advantage, but its lineup also laps Washington's in runs scored per game, hits per game, batting average, slugging, OPS and home runs.

We're also catching a solid price on Minnesota's run line at -110 on bet365.

Pick: Twins -1.5 (-110 | Play to -115) 

  • Check out the latest bet365 bonus code offer before placing your bets on Twins vs Nationals.

Tigers vs. Royals

Tuesday, May 21
7:40 p.m. ET
Tigers ML (-108)

By D.J. James

The Detroit Tigers are starting to hit, especially against right-handed pitching.

They're lucky because they get to face one on Tuesday in Kansas City's Alec Marsh.

Marsh has been decent, but the regression monster will come for him eventually. His average exit velocity allowed is almost 89 mph. He doesn't keep the ball on the ground, and his strikeout rate is only a touch above 20%. He's serviceable but clearly overperforming (2.43 ERA, 4.11 expected ERA).

His opponent will be Casey Mize, who is starting to look like a fixture atop the Detroit starting rotation. The former first-overall pick ranks in the 84th percentile among qualified pitchers in ground-ball rate. He also rarely walks anyone. His ERA and expected ERA sit in the mid-3.00s.

The lineups make the handicap. Kansas City only has a 91 wRC+ off of righties in the last month with a pedestrian 7% walk rate. Conversely, Detroit boasts a 113 wRC+ off of righties during that stretch. The Motor City Kitties are primed to force the regression monster upon Marsh.

In relief, the Tigers have a combined 3.90 expected FIP across the last month with a sub-8% walk rate.

Meanwhile, Kansas City’s relief staff has given them headaches this year. Since April 21, the Royals boast a 4.23 expected FIP and a sub-20% strikeout rate.

Take the Tigers in this one.

Pick: Tigers ML (-108 | Play to -127) 

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