Zack Wheeler's 100 MPH Fastball Makes Him Overlooked Trade Steal of 2019

Why trade for, say, a Madison Bumgarner when there's a perfectly good Zack Wheeler right there? 

The New York Mets surely wish this wasn't a question. Alongside fellow flamethrowers Jacob deGrom and Noah Syndergaard, Wheeler was supposed to anchor a dominant starting rotation in 2019. As a whole, the Mets were supposed to be a contender.

As they are wont to do whenever the Mets are involved, however, the baseball gods have had other ideas.

Wheeler is one of many Mets players who've fallen short of expectations, as he's following a 3.31 ERA in 2018 with just a 4.42 ERA this season. Meanwhile, the Miami Marlins are the only National League team with a worse record than the Mets' 39-48.

The Mets almost certainly won't go into fire-sale mode ahead of the July 31 trade deadline. But with Wheeler, their choices boil down to either trading him or potentially losing him to free agency this winter.

Hence why the trade chatter surrounding Wheeler is only getting louder. According to Andy Martino of SNY.tv, the New York Yankees, Atlanta Braves and Milwaukee Brewers are among the teams with interest in the 29-year-old right-hander:

Those aren't the only contenders that could use Wheeler. Others that have starting rotation needs include the Tampa Bay Rays, Boston Red Sox, Minnesota Twins, Houston Astros, Texas Rangers, Oakland Athletics, Philadelphia Phillies, St. Louis Cardinals and Colorado Rockies.

Some of these clubs might prefer a starter with more club control, such as Toronto Blue Jays right-hander Marcus Stroman (through 2020) or Detroit Tigers left-hander Matthew Boyd (through 2022). 

As far as rental options go, Bumgarner certainly has a shinier profile than Wheeler. His 11 seasons with the San Francisco Giants have yielded a 3.09 career ERA, four All-Star selections and three World Series championships. He even has a better ERA (4.02) than Wheeler this season.

But if nothing else, Wheeler is cheaper than Bumgarner. The latter is making $12 million. The former, only $6 million. Yet due to his relative lack of accolades and disappointing results, Wheeler's acquisition cost might be lower than Bumgarner's anyway. He's not quite a buy-low candidate, but he isn't a buy-high candidate either.

Track records and ERAs aside, it's also easy to argue that Wheeler is the better pitcher right now.

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Consider xwOBA, which measures the expected production against pitchers based on their strikeouts, walks and quality of contact. Here's how it stacks up with Bumgarner and Wheeler: 

• Bumgarner: .332 xwOBA
• Wheeler: .302 xwOBA

Three related stories are that Wheeler's strikeout, walk and home run rates are all better than average. The same goes for his hard and soft contact rates. His overall contact rate is above average, but his below average contact rate within the strike zone speaks to the sheer electricity of his stuff.

The Mets defense likely hasn't done Wheeler's results any favors. It ranks 26th in efficiency and 28th in defensive runs saved. He's also thrown primarily to Wilson Ramos, who rates as a below-average pitch framer.

An enterprising team might consider all this and conclude that a change of scenery is all Wheeler needs. An even more enterprising team might look at him and consider how he might be Justin Verlandered.

This is in reference to what became of Verlander after he was traded from the Tigers to the Astros in August 2017. He was already a Cy Young-caliber pitcher. But as he would later tell Ted Berg of USA Today, he changed how he threw his slider and gained a better understanding of his general strengths and weaknesses upon joining Houston.

The results have been overwhelming. Verlander has gone from a 3.49 ERA as a Tiger to a 2.50 ERA as an Astro. Likewise, his strikeouts-per-nine rate has jumped from 8.5 to 11.7.

Facilitating a similar change with Wheeler won't be as straightforward. Any team that trades for him might only have two months to work with him. And by his own admission, Wheeler isn't much for change.

"Honestly, I hate change," he told Marc Carig of The Athletic.

Nevertheless, a process for getting Wheeler to change for the better might be as simple as zeroing in on his fastball and slider.

Only Syndergaard (97.7 mph) is topping Wheeler's average fastball velocity of 96.8 mph, and he's been clocked as high as 100.6 mph this season. Wheeler's average slider velocity (91.8 mph) ranks second to only deGrom, and he's thrown it as hard as 95.4 mph.

And as pitching analyst Rob Friedman demonstrated, Wheeler already knows how to make these two pitches work together:

Wheeler actually struggled with his slider earlier in the season, but hitters' batting average and slugging percentage against it have since come down.

As he told Tim Britton of The Athletic in June, there's a reason for that:

"[I'm] just staying behind the ball more. Staying behind the ball allows me to get on top of the ball, if that makes any sense, rather than being around the ball and it moving (horizontally). So I’m staying behind the ball, allowing my fingers to get over the front of it, which allows you to get the depth and the movement that you want."

Lo and behold, the average vertical movement of Wheeler's slider is getting lower as the season moves along. Perhaps all he needs to do now is make more frequent use of his slider, as it's thus far accounted for only 18.3 percent of his pitches.

Then there's Wheeler's fastball. Or, more accurately, fastballs. He throws both a four-seamer and a two-seamer, and contrary to many pitchers today, he actually prefers the latter. Given how nasty it can be, that's understandable.

And yet hitters are slugging .459 against Wheeler's two-seamer as opposed to just .313 against his four-seamer. That's potentially a cue for him to revert back to his pitch mix from his breakthrough 2018 season, when he threw 42.3 percent four-seamers and only 15.2 percent two-seamers.

Ultimately, Wheeler doesn't come with as many glaring red flags as his top counterpart on the rental starter market.

Bumgarner is past his prime and beset by red flags. At the least, Wheeler is a talented pitcher who's owed better results. At best, he's a talented pitcher who might quickly be transformed into an ace.

In either case, he's absolutely worth renting for the rest of the season.

Data courtesy of Baseball Reference, FanGraphs, Baseball Savant, Baseball Prospectus and Brooks Baseball.