Brendan McKay will make his major-league debut Saturday, Marc Topkin of the Tampa Bay Times reports.

To be clear, it'll be as a pitcher.

The distinction is necessary because he was regarded more as a first baseman when the Rays selected him fourth overall in the 2017 draft. They made the bold decision to play him both ways, though, and sure enough, he flourished the other way.

There are a number of questions surrounding his arrival, but none of them have to do with ability. In 13 appearances, including 11 starts, between Double- and Triple-A this year, he compiled a 1.22 ERA and 0.80 WHIP, striking out 88 and walking just 15. That's actually a worse strikeout-to-walk ratio than he had last year, when he turned in a 2.41 ERA and 0.88 WHIP between three levels.

What made his quick rise up the minor-league ladder all the more impressive is that his attention was divided during it. While his bat has been slow to develop, it's almost like his arm was major league-ready from the day he was drafted.

And now we'll get to find out if it's fully like that.

But there are some caveats:

  • We don't know if it's intended to be just a spot start. Ryan Yarbrough, who was expected to pitch the bulk of Saturday's game (whether as a true starter or following an opener) was needed for three innings in the Rays' 18-inning affair at the Twins Thursday, which prompted McKay's promotion. Will the Rays make room for the 23-year-old lefty beyond that? It's almost a true bullpen day whenever Jalen Beeks' turn comes up to pitch — he rarely provides the length that Yarbrough or Yonny Chirinos do — so you'd think a path would exist right there.
  • We don't know if McKay will be permitted to go beyond five innings. That's been the limit for him at Triple-A (by design, not just happenstance), though he did pitch six innings three times while still at Double-A. The goal was to preserve innings for the big club later in the season — he threw only 78 1/3 last year and is already up to 66 2/3 this year — but now that he's in the bigs, is that incentive still there? Not like he's making it to October either way.
  • We don't know, in the case that he is limited to five innings, if he'd be following an opener (as he did twice in the minors). It would actually be preferable in most Fantasy formats since the chances of a pitcher collecting a win are directly tied to how late he exits with a lead. Five-inning pitchers typically don't come away with too many. Of course, if you play in a league that rewards quality starts, McKay wouldn't be getting any of those in this scenario. 
  • We don't know if he'd be working every sixth day, like he was in the minors. Doing so would create complications throughout the Rays rotation and would greatly reduce the possibility of McKay being a two-start pitcher in a given week. But again, preserving his innings may not be as much of priority for however long he's in the majors.
  • We don't know if the Rays are ready to give up on him as a two-way player. It doesn't seem like they're in a place to let him take his lumps as a hitter in the majors, so if they're not ready to abandon that plan, it's all the more reason why they'd send him back down. Maybe they'll wait until he exhausts his innings supply, though.

So there you have it. While with most big-time prospect call-ups, you can just sit back and enjoy the ride, there's nothing straightforward about this one.

Nonetheless, you have to add McKay. You have to. The need for dependable starting pitching is too great in an environment where home runs are being hit at a record pace, and his track record would certainly suggest he's a candidate for such, even if there are some limitations attached.

And there may not be any limitations, really — at least not beyond those you'd expect for any young pitcher — in which case you'd be a sucker for passing him up. We've all suffered through the ups and downs of what we thought would be our ace, whether it's Blake Snell or Noah Syndergaard or Aaron Nola or James Paxton, and we've all gotten burned chasing the latest hot-ticket item, be it Joe Musgrove or Martin Perez or Nick Pivetta or Framber Valdez, all in the hope of creating a little stability in what has become the game's most volatile economy.

So when you have a shot at genuine upside, you find a spot for it and figure out the rest later. If it doesn't work out, you're not in any worse of a state then you were in before. 

Realities being what they are, though, I suppose there may exist a scenario wherein you may not be able to find a spot for someone like McKay, with all the questions surrounding him. I would hope you're dominating your league in such a scenario, but either way, here's where the rubber meets the road:

I have McKay 58th among starting pitchers in my rest-of-season rankings. I wouldn't drop the recently promoted Zac Gallen for him, and I wouldn't drop the soon-to-be-promoted Jesus Luzardo for him. The potential rewards being what they are, though, I'd try to find someone I could drop for him.