After months of anticipation dating back to last season, highly-touted Diamondbacks pitching prospect Brandon Pfaadt made his major league debut on Wednesday against the Texas Rangers. Suffice it to say it went as poorly as anyone could have imagined.

In 4 2/3 innings of work, Pfaadt allowed seven runs on nine hits with one walk and three strikeouts. More batters homered against him than struck out.

While Pfaadt’s debut did not inspire confidence for what many hope will be a long and successful career ahead, it was only one start. His pitch mix looked good, and, with better command, his results could change in a hurry.

Here are five takeaways from Pfaadt’s debut.

1. Command, not stuff, was the problem

Pfaadt’s esteemed prospect status has never been tied primarily to his stuff. It has always been good, but not elite. Pfaadt is the type of pitcher who needs to locate well to succeed. He has done that well in the minors the past two seasons, but he did not do that well on Wednesday.

Here is a chart of all of Pfaadt’s pitches in his debut:

Pfaadt threw too many four-seamers in the middle of the zone, too many sliders in the middle of the zone and too many changeups that either caught too much of the plate or were too far off it to warrant a swing-and-miss.

Despite what Pfaadt’s alarming box score numbers say, he was not all that bad on Wednesday. He just did not locate his pitches well, and the Texas Rangers — who rank in the top 10 in the league in nearly every offensive category — made him pay for it.

In the second inning, Rangers catcher Jonah Heim got a hanging 90 mph changeup and did not miss it.

In the fourth, Pfaadt tried to get this slider to the lower-outside corner against reigning AL Rookie of the Month, Josh Jung. Instead, it ended up middle-in, and Jung deposited it into the seats.

In the fifth, Leodys Taveras capitalized on another hanging Pfaadt changeup.

The good news for Pfaadt is that command has generally been a strength, and it seems unlikely that he will struggle to this degree in future starts. With this first one out of the way, perhaps he will be more relaxed heading into his next outing, which is lined up for next Tuesday against a much tamer Miami Marlins offense.

2. Pfaadt should throw fewer strikes

Wait, didn’t we just say that Pfaadt’s command was off? That means he needs to throw more strikes, right? Not necessarily. Sometimes, pitchers have poor command and also pound the strike zone. The issue with Pfaadt’s command was not that he could not throw strikes, but that the strikes he threw were in the wrong places.

Now, we take things one step further: Pfaadt actually should throw fewer pitches in the strike zone altogether.

For the game, Pfaadt threw 60 percent of his pitches in the strike zone. In technical terms, we say that he had a zone rate of 60 percent. For reference, most D-backs pitchers this season have zone rates below 50 percent. Ryne Nelson has the highest zone rate on the team at 57.4 percent.

Initially, the idea of throwing fewer pitches in the zone might sound like a bad thing. Don’t pitchers want to throw strikes? Generally, yes, but not all the time. Throwing a steady diet of well-executed pitches outside the zone keeps opposing hitters off balance, and can lead to more whiffs and weak contact.

Granted, Pfaadt struggled to get Rangers hitters to chase pitches out of the zone on Wednesday, which naturally meant throwing more pitches in the zone to stay ahead in counts. Out of the 35 pitches that he threw out of the strike zone, Rangers hitters only swung at six of them. As Pfaadt gets better at landing his off-speed pitches in enticing locations outside of the strike zone, he will buy himself more freedom to throw those types of pitches.

Filling up the zone to a fault has been a trend for Pfaadt throughout his time in the minors. Expanding in pitcher-friendly counts was a point of emphasis for him last season, and it’s something he probably needs to continue working on. Even if doing so means occasionally walking an extra batter here or there, it should be a worthy tradeoff.

3. Pfaadt’s slider has real swing-and-miss potential … when thrown in the right pace

Pfaadt’s slider is his best pitch, and it is not hard to see why. It has elite spin that results in sharp horizontal movement and surprisingly little downward break. There are not many sliders out there like it.

In the second inning, Pfaadt threw what might have been his best one of the game to notch his first big league strikeout.

In total, Pfaadt threw 17 sliders in the game. Texas hitters swung at 10 of them, missing four times. That works out to a 40 percent whiff rate, which is essentially identical to Zac Gallen’s whiff rate on both his curveball and changeup. (In other words, it is very good.)

As alluded to earlier, however, getting Rangers hitters to chase the pitch out of the zone was a challenge. Of the seven sliders that Pfaadt threw out of the strike zone, only two induced swings from Rangers hitters. Neither of them resulted in a whiff. Ironically, all four whiffs on Pfaadt sliders came on pitches that were in the strike zone.

Pfaadt’s slider is good enough that it can get whiffs in the zone, but, ideally, he should be trying to get those whiffs just off the edges. He was unable to do that consistently in his first big league start.

4. Home runs may, indeed, be a problem

If there is any knock on Pfaadt’s game, it is probably that he has been relatively home-run prone during his time in the minors. Frankly, any pitcher would be homer-prone in the extreme hitter-friendly environments that D-backs prospects deal with in Double-A and Triple-A. Still, Pfaadt’s home run problem showed up in a big way on Wednesday, as the Rangers blasted four dingers against him.

Based on how Pfaadt uses his arsenal, it was probably reasonable to expect his home run woes to follow him into the big leagues, to some degree. After all, he has always been a fly-ball pitcher. Generally, more fly balls lead to more home runs. His fly-ball tendencies stem in part from the fact that he likes to throw his fastball up in the zone, where it gets more whiffs but also runs a higher risk of getting hit over the fence.

On Wednesday, three of the four homers against Pfaadt came on off-speed pitches that were left up in the zone. As for any pitcher, cutting down on those mistakes will be crucial to limit homers in the future. Frankly, even if he does, there may always be a few more homers on Pfaadt’s stat-line than either he or the Diamondbacks would like.

5. Torey Lovullo should have taken Pfaadt out sooner

The Diamondbacks entered the fifth inning of Wednesday’s game with a 6-2 lead. It made sense to have a relatively long leash on Pfaadt, who could earn the win if he finished the inning with a lead.

When the inning ended, Pfaadt was in line to take a loss instead, and it was abundantly clear — even to D-backs manager Torey Lovullo himself — that the leash on the D-backs’ rookie was longer than it should have been.

“Maybe I left him out there an at-bat too long,” Lovullo told the Arizona Republic. “I was trying to get him through five. I knew we were a little short in the bullpen. I can give you every excuse that’s a reason why I did it. I shouldn’t have.”

The inning began with a solo homer by Leodys Taveras that made it a 6-3 game. After a pair of doubles by Sandy Leon and Travis Jankowski, the Rangers cut the deficit to two runs with still with only one out in the inning. A Nathaniel Lowe single put the tying runs on base for baseball’s RBI leader, Adolis Garcia. One could make the case that Lovullo should have removed Pfaadt right there.

Instead, Pfaadt continued, and Garcia rocketed a fly ball to center field. Fortunately for the D-backs, there was just enough room in center field for Alek Thomas to turn it into a sacrifice fly. The D-backs’ lead was cut to 6-5, and up came Jung, who had already homered against Pfaadt earlier in the game. Disaster struck again, as Jung smashed a go-ahead, two-run homer that put the Rangers out in front.

Ultimately, it was Pfaadt who allowed four homers on Wednesday, not Lovullo. But Lovullo could have prevented one of them. Fortunately for the D-backs, that fourth homer did not keep them from winning the game.

Frankly, even if Pfaadt had not allowed that fourth homer, his long-awaited big league debut still would not have been what many hoped it would be. Pfaadt was just not good on Wednesday.

Even so, it was only one start. It came against one of the most prolific offenses in the sport — and in a top-down Globe Life Field that had baseballs soaring all afternoon.

Pfaadt will be back, and he will probably be much better.

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Top photo: Jerome Miron/USA TODAY Sports