Who needs a pitcher?

The Mariners need a pitcher, which is why Andrew Moore has gotten the call to start Thursday's game against the Tigers. He's bumping Yovani Gallardo, too, which tells me they view him as an upgrade, not a fill-in.

The Reds need a pitcher, which is why Luis Castillo is getting the call to start Friday's game at the Nationals. Bronson Arroyo kind of forced their hand by straining his shoulder and talking about retirement, but their entire rotation is replaceable.

Shoot, we all need a pitcher in a year when offense is once again taking over the game, putting us forever in pursuit of reliability.

Moore and Castillo may not be immediately familiar to you, but both could stick around and both on some level meet the definition of "prospect."

So which would I rather have? Well, I'm not rushing to pick up either outside of AL- and NL-only formats, dynasty or otherwise, but either could win me over with his performance, as Jacob Faria did. Shoot, I was picking up Buck Farmer everywhere I could after just two good starts, and calling him a "prospect" was always a stretch.

Moore and Castillo both control the strike zone in a way we don't often see from minor-leaguers, each averaging fewer than 2.0 walks per nine innings this year, but Moore is the tougher sell for me because that's the only way he stands out. He gets a lot of spin on his fastball, which helps it play up, but it sits in the low 90s. His secondary arsenal also leaves something to be desired.

Castillo's arsenal, on the other hand, is a scout's dream. He reaches triple digits with his fastball and offsets it with a picture-perfect changeup. His breaking ball is a work in progress, but there's potential there as well. The control, though, is the most impressive quality for someone who throws as hard as he does.

"He's throwing good stuff, he's throwing strikes. You know, that's really what we need," manager Bryan Price told the Cincinnati Enquirer. "That doesn't mean that's how it's going to translate here, it can be even better in the big leagues than he's been in Double-A with a big-league defense behind him on a big-league field. What's jumping off the page is not just the ERA, which is nice, but it's the fact that he's commanding the strike zone. He's throwing three pitches over." 

My biggest hesitations with Castillo are that he's making the jump straight from Double-A and that the Reds haven't had much success breaking in their pitching prospects in recent years. Given that he has allowed no more than three earned runs in any of his last eight starts, though, recording double-digit strikeouts in three, he's the one I might consider adding ahead of his debut.

Now then, for the players still in the minors ...

Five on the verge

(These are the prospects most worth stashing in redraft leagues.)

Kyle Schwarber, OF, Cubs

2015 majors: .246 BA (232 AB), 16 HR, .842 OPS, 36 BB, 77 K
2017 majors: .171 BA (222 AB), 12 HR, .673 OPS, 36 BB, 75 K

How stupid is this? You come looking for prospects -- relative unknowns who might sneak up on the traditional Fantasy-playing world -- and instead, you get a player whose name is already part of postseason lore. Schwarber is technically a minor-leaguer, though, and what he provides for us here is context. If he's indeed the most stashable of the minor-leaguers and you want nothing to do with him, well, that gives you some idea just how un-stashable every minor-leaguer is in your particular format.

What struck me when filling in his stats is the intermittence of his career so far. I had to go back to 2015 to find a second stat line of any real size. He was rushed and then left to rust, but as easy as he made the minors look the first time around, batting .333 with a 1.042 OPS in what amounts to a full season, here's hoping for a quick turnaround.

Yoan Moncada, 3B, White Sox

2016 minors: .294 BA (405 AB), 15 HR, 45 SB, .918 OPS, 72 BB, 124 K
2017 minors: .282 BA (234 AB), 8 HR, 14 SB, .819 OPS, 42 BB, 75 K

Speaking of quick turnarounds, Moncada has mostly put the concerns over his thumb to rest, bouncing back from his first true slump of the season with a .375 (9 for 24) batting average over his last six games. What impresses me most about that stretch, though, is the seven walks to four strikeouts -- improvement in the one area (plate discipline) where evaluators are still unsure about him. It's a laughable sample, of course, but now that Super 2 concerns are behind us, it won't take much for the White Sox to get on board.

Amed Rosario, SS, Mets

2016 minors: .324 BA (479 AB), 5 HR, 19 SB, .833 OPS, 40 BB, 87 K
2017 minors: .325 BA (286 AB), 7 HR, 12 SB, .847 OPS, 17 BB, 49 K

It might take the ground opening up and swallowing their entire infield for the Mets to get on board with promoting Rosario. Shoot, we've seen that scenario play out at least halfway this week, with both Asdrubal Cabrera (thumb) and Neil Walker (hamstring) landing on the DL, but instead of Rosario's dynamic talent, we were treated to Gavin Cecchini. I have absolutely no idea what the Mets are thinking unless they're so terrified of sticking Rosario with Super 2 status that they're guarding against a record late date. Come the start of the second half, he's up, I bet.

Derek Fisher, OF, Astros

2017 minors: .335 BA (245 AB), 16 HR, 13 SB, 1.010 OPS, 25 BB, 53 K
2017 majors: .278 BA (18 AB), 2 HR, 1 SB, .992 OPS, 3 BB, 5 K

George Springer's injury scare -- he left Thursday's game after getting hit on the hand in the first inning -- was a welcome reminder of just how close Fisher is to returning to the Astros outfield. Manager A.J. Hinch called his demotion, coupled with Josh Reddick's return from the DL, "a bittersweet move," and I suspect that if Jake Marisnick hadn't caught fire, it wouldn't have happened at all. It's basically just a Marisnick slump or any kind of injury standing in Fisher's way, and in his brief trial, he gave us every reason to believe his power breakthrough is legit.

Blake Snell, SP, Rays

2017 minors: 0-4, 4.71 ERA, 1.62 WHIP, 42 IP, 25 BB, 34 K
2017 majors: 5-0, 2.66 ERA, 1.32 WHIP, 44 IP, 15 BB, 61 K

Remember him? He's beginning to find his form at Triple-A Durham, cutting his walk rate to 2.5 per nine innings in his last five starts -- and while still averaging 11.1 strikeouts per nine. Even during the stretch that earned him his call-up last year, he averaged 4.0 walks per nine. His stuff is electric, and his next opportunity should come sooner than later with swingman Erasmo Ramirez barely clinging to a rotation spot and Matt Andriese sidelined for an extended period. It's time to think about picking up Snell again.

Five on the periphery

(These are some other prospects doing something of note.)

Brendan Rodgers, SS, Rockies

2016 minors: .281 BA (442 AB), 19 HR, 31 2B, .821 OPS, 35 BB, 98 K
2017 minors: .400 BA (210 AB), 12 HR, 21 2B, 1.119 OPS, 6 BB, 31 K

Chalk one up for projection and player development. Rodgers numbers the last couple years may have underwhelmed given his top prospect standing, but he only turned 20 this year. He's just now developing his man muscles, and the early returns are so good he's already making the leap to Double-A ... again, at age 20. You could knock the plate discipline, I guess, but when the day comes for Rodgers to play at Coors Field, I'm thinking the Trevor Story hype will look pretty silly in retrospect.

Mike Soroka, SP, Braves

2016 minors: 9-9, 3.02 ERA, 1.13 WHIP, 143 IP, 32 BB, 125 K
2017 minors: 8-3, 2.23 ERA, 0.94 WHIP, 76 2/3 IP, 16 BB, 69 K

Sean Newcomb is just the tip of the iceberg as far as Braves pitching prospects go. At Double-A is where we really begin to see the fruits of their rebuild, and Soroka is quickly emerging as Exhibit A. The 19-year-old (as if that isn't impressive enough) is riding a 25-inning scoreless streak at what's often considered to be the most difficult step up the minor-league ladder. His maturity and pitchability should get him to the majors before his 21st birthday.

"He's definitely way ahead of his years and there's still going be some growth to his game," Mississippi pitching coach Derrick Lewis told MLB.com. "Every start is something new. He goes out there and he keeps adding to his game every start. Each time out, he does something a little different and learns something new from every outing." 

Nick Senzel, 3B, Reds

2016 minors: .305 BA (243 AB), 7 HR, 24 2B, 18 SB, .912 OPS, 38 BB, 54 K
2017 minors: .305 BA (246 AB), 4 HR, 26 2B, 9 SB, .847 OPS, 23 BB, 54 K

Another prospect on the fast track, Senzel is moving up to Double-A after tearing up the Florida State League with a ridiculous doubles pace. He'll need to turn some of those doubles into home runs to live up to expectations as a former second overall pick, but he's still growing at age 21. So far, he's looking like one of the top prizes of the 2016 draft class and remains a valuable commodity in long-term keeper leagues.

Austin Hays, OF, Orioles

2016 minors: .336 BA (140 AB), 4 HR, .900 OPS, 11 BB, 32 K
2017 minors: .328 BA (262 AB), 16 HR, .956 OPS, 12 BB, 40 K

One of the more overlooked prizes of the 2016 draft class, having lasted to the third round, Hays ended the first half going 5 for 5 with two home runs, and together, he and Michael Chavis (who has gotten several mentions in this space this year) lead the Carolina League in just about every offensive category. Even in leagues that venture deep into the minor-league pool, there's a chance Hays is unowned given the lack of hype coming into the year, but he's a legit prospect now.

Tyler Mahle, SP, Reds

2016 minors: 14-6, 3.64 ERA, 1.15 WHIP, 150 2/3 IP, 37 BB, 141 K
2017 minors: 7-3, 1.59 ERA, 0.87 WHIP, 85 IP, 17 BB, 87 K

Mahle is moving up to Triple-A after making a mockery of the Southern League over the first three months, and considering the Reds just turned to a Double-A pitcher, Luis Castillo, to fill their latest rotation opening, you have to think Mahle isn't too far behind. He throws a ton of strikes, which has been an issue for the Reds young pitchers, but he pretty much lives and dies with his fastball. It's an awfully good one, but Mahle's secondary arsenal will be put to the test when he eventually gets the call.