As Susan Slusser with the San Francisco Chronicle reported on Wednesday, Sean Manaea will be called up to start Friday’s game in Oakland against Mike Fiers and the Houston Astros. Manaea made a decent case for making the rotation out of spring training, tallying 16 strikeouts in 14.1 innings, but the seven walks allowed over the same period gave the A’s enough reason to start him in Triple-A Nashville.

Across three starts in Nashville, he has been lights out on the mound. Only three runs have crossed the plate against him in 18 innings pitched, while 21 batters have struck out and just four have reached via free passes. That level of performance was enough for Oakland to feel comfortable bringing him up to the majors in lieu of a fourth appearance for the Sounds. But what can we expect from him out of this start, and (presumably) those going forward in an A’s uniform?

When I saw him in the fall, I was impressed by his potential but worried about his consistency. From my Oakland A’s prospect report:

His stuff ranged from below-average to plus from one game to the other, and it was often true of his secondary offerings from pitch to pitch. All together, his command looks like it’s going to max out around average, if it makes it that far, and combined with the grades his pitches will get to makes him a most likely number four starter, with a chance at being a three. Concerns about his fluctuating velocity are well-founded, working 89-93 one game and 92-95 the next. His low-80s slider flashed plus in his earlier start, but looked like a 40 or 45 for most of the second. A changeup is used as a viable third pitch, though he telegraphs it with a slowed down arm and exaggerated pronation. It too flashed above-average to plus in one or two at bats. He uses a drop-and-drive delivery that starts out uphill, more so than he ever did in college. Most successful pitchers who use that start have a consistent means to stay balanced, but Manaea hasn’t found it yet. Sometimes he gets back on top of his legs, while others he stays back and spins to deliver the ball from a slightly leaned back landing posture. The inconsistencies seem to stem from instability in his lower half, which makes you wonder how much his previous hip injury and more recent core injuries have sapped his strength and mobility.

And the video from one of his starts in November:

You can see he had a pretty easy-going delivery and a consistent stride direction, but the stability of his landing leg varied quite a bit from pitch to pitch. I posited that this was due to having less than optimal control of his hips as he began his stride, which threw off his balance just enough to cause his command and velocity to waver. Fast forward to this season, and some of the concerns remain, while others seem to be improving for Manaea. From this spring:



Video courtesy of Major League Baseball

In the more recent footage, Manaea looks more sure-footed and strong on his front leg, giving him a more consistent base from which to deliver the baseball. I was able to see his most recent start on April 22, as well, which offered a similar look to the one here. The main difference is he looks even more effortless with his arm, lending hope that he can carry his recent solid control over into the big leagues. According to MLB.com, his 67.4% strike rate (not zone rate, mind you) is well above his minor-league career norms to date.

The other big plus going for him is his fastball velocity. While I did see him in the 94-95 range a few months ago, he didn’t come close to it in a subsequent start, and it noticeably dropped off as each game progressed to the later innings. Now, he’s sustaining the upper end of his velocity band from start to finish, owing in no small part to what looks like a stronger lower half. He’s commanding his fastball better, as well, and he has a good feel for burying his slider down out of the zone on his glove side for swings and misses.

Despite the improvements, he’s not a complete slam dunk yet. He still has the tendency to collapse on his back side as he strides, putting him in an uphill position that can cause issues with his release point changing in all three planes. It’s mitigated to a degree by a firmer front leg to keep everything together, but he ends up leaving balls up and over the plate as a result.

This is especially true of his offspeed pitches. Though he has done an excellent job of putting hitters away when he gets to two strikes, he hasn’t yet shown the feel to keep his changeup or slider out of the big parts of the zone when attempting to locate those pitches on the edges. If hitters will let him get ahead in the count, Manaea won’t have much of a problem continuing to strike hitters out at an above-average level.

Lastly, his changeup is relatively unchanged from my previous looks. The speed differential is fine, and he can get a little fade on his best ones, but he hasn’t learned how to consistently sell it yet. His delivery and arm speeds are distinctly slower on the pitch, and major-league hitters are nothing if not extremely observant of subtle hints that pitchers give away about an upcoming pitch. Just a bit too much information can be gleaned before release to expect his change to be more than a distant third offering right now.

For the long term, I’m cautious about going too much higher than my 50/55 (likely/ceiling) overall grades I gave Manaea in the prospect write-up, though I am tempted to bump each up a half grade. I don’t want to let a decent spring and three strong regular-season starts change my assessment without more of the concerns being alleviated. It’s important to remember how much health has limited his development thus far, especially when those injuries directly relate to performance consistency when he’s on the field. If we could guarantee his health — and the corresponding velocity/command bumps — I’d be all for it.

In the meantime, he is pitching like he’s fully healthy, and hopefully it stays that way long enough to continue sharpening the finer points of his game. Apart from the more important skills above, he has work to do controlling the running game. While neither Stephen Vogt or Josh Phegley are tremendous receivers behind the plate, both are adept at helping out against aggressive base-runners, so that shouldn’t be a huge issue for him.

Even though there are some shortcomings to iron out, fastball velocity and strike-throwing have a way of compensating for a lot of weaknesses. His changeup may play better than I give it credit solely because of his mid-90s heat. We’ll have to see how hitters do against him, preferably after a time or two through the lineup and multiple starts.

Manaea’s first test will be against the dangerous Houston Astros’ lineup. Their overall production so far this year has them toward the back of the top 10 in the majors as a unit, but their collective ability to punish pitcher mistakes makes them a formidable opponent. They lead the league in pitches per plate appearance, ideally giving Manaea more opportunities to get ahead in the count. They also lead the league in strikeouts despite being the most aggressive team on balls in the strike zone.

Everything comes down to execution on Manaea’s part; if he can minimize the potential damage by throwing strikes on the corners early in at-bats, the Astros lineup will swing and miss enough for his debut to go swimmingly. If his get-me-over sliders and first-pitch fastballs catch too much of the middle of the plate, they will let him know in a hurry the difference in room for error between Triple-A and the American League. It all adds up to an exciting matchup that could go any way imaginable.