The A's won't hesitate to bring up Manaea, ranked as Oakland's No. 2 prospect by MLBPipeline.com, no matter the ramifications such a move would have on his service time clock, as executive vice president Billy Beane said this spring.
"If you think it's going to hurt them, you don't [promote them]," Beane said. "What doesn't come into play from my end is the whole contractual thing.
"If we deem them ready, or we think they would benefit or wouldn't be harmed by being here, we bring them up, and that's the way I feel with Sean. That's my position. I have internal debate on that. There are plenty of people who push back with me. But if I think he's one of the five best guys and he won't be harmed by being here, then I wouldn't have any reservations about using him."
The 24-year-old Manaea, who was 6-0 with a 1.90 ERA in seven starts for Midland after his acquisition from the Royals, features a fastball in the upper 90s, and his size and funky delivery make for deceptive movement.
The A's saw these very attributes on display several times this spring. Manaea made five appearances, including three starts for the club, before being sidelined with a minor groin injury. He finished his first big league camp with a 4.40 ERA, allowing seven earned runs in 14 1/3 innings with 16 strikeouts and seven walks.
"For how big he is, very smooth delivery," catcher Josh Phegley said. "It looks really clean. The ball comes out of his hand nicely. He keeps the ball down in the zone, and from that height, he gets some big-time tilt."
The A's will begin the season with a rotation that includes Sonny Gray, Rich Hill, Chris Bassitt, Kendall Graveman and Felix Doubront, with Jesse Hahn awaiting his turn at Triple-A as the sixth option. But Manaea, the organization's top pitching prospect, is considered next in line.
All but Gray, the lone homegrown arm, were brought in via trade, as the A's have made a concerted effort to bulk up an area that was lacking in depth.
"Pitching is always the thing I worry about here," Beane said. "We've been behind the pitching curve since Jarrod [Parker] and [A.J.] Griffin went down. We're constantly looking for starting pitching prospects, because any successful run we have here is going to be based on controllable, organic starting pitching. You're not going create a starting staff that's playoff-caliber by picking up mid-level free agents.
"Pitching is one area we're always kind of panicked about a little. There's an attrition with pitchers. It's expensive, and it is volatile in terms of its performance. We have some kids coming, including Manaea, but still, that's not enough. You need a lot of guys."
Manaea, at least, is the poster boy for the kind they eye.
"There's a lot with this guy to be excited about," manager Bob Melvin said. "You can understand what all the hoopla is about when he looks to be a very talented guy with an assortment of pitches."
"There are a lot of great things happening right now," Manaea said. "I just want to keep working hard."