The Rockies were a popular sleeper pick before the season began. It got to a point where they were so often picked as the surprise team in the National League that they could hardly be considered sleepers. But then March happened. The team suffered several injuries to some significant players—David Dahl, Ian Desmond—and they lost starting pitcher Chad Bettis to cancer treatment. That dampened some spirits. And then it got worse when April happened. Jon Gray, the Rockies’ best pitcher, broke his foot fielding a pitch early in his third start of the season. The Rockies were faced with losing two-fifths of their rotation, and they had to turn to a cadre of rookies to fill in.

And then a bunch of winning happened. Analysts have asked the reasonable question, “how have they done it?” The consensus answer is that the young squad is generating a huge amount of groundballs, and the infield defense has been excellent in turning those into outs. The rotation of Tyler Anderson, Tyler Chatwood, Kyle Freeland, Antonio Senzatela, and Germán Márquez has been solid so far, but something is going to have to give when Gray returns sometime in June. Here are some possibilities.

Someone goes back to the minors

It wouldn’t be one of the Tylers, the relative veterans of the group, and it probably wouldn’t be Freeland. Freeland currently leads all of baseball with a 65.9 percent groundball rate. He’s had some trouble with walks, and he’s been a bit fortunate with suppressing home runs. Currently, just 4.3 percent of the fly balls Freeland has allowed have been home runs. Last season, Johnny Cueto led all qualified pitchers in that category with an 8.4 percent mark. There has been only pitcher since 2012 to post a lower HR/FB, Garrett Richards in 2014. While there are pretty obvious areas in which Freeland will likely have trouble with going forward, he’s been as polished and mature as advertised. He’s unlikely to get sent back down when Gray comes back.

That leaves Márquez and Senzatela. Going by the principle of last one up first one down, Márquez would be the one to be sent down. He doesn’t have a lot of Triple-A experience, so it could make sense (he’s pitched 41 innings at that level in his career). Much of it might depend on which Márquez shows up over the next two weeks. He’s had four starts so far, two very bad and two very good. In his two bad starts, he’s given up 13 runs in 10 innings of work while striking out five. In his two good starts, he’s allowed 0 runs in 14 innings while striking out 16. Presumably, he’ll have some starts in the middle. If Márquez finds a groove, there’s no way the Rockies can send him down.

Senzatela earned a rotation spot out of spring training. This was surprising since he hasn’t pitched at all in Triple-A, and he has just 342⁄ 3 Double-A innings. He’s been walking the razor’s edge more than any other Rockies pitcher as well. While he’s walked fewer batters than Freeland, he’s also struck out fewer, and he’s not generating groundballs anywhere near the clip Freeland is. If he continues to post an ERA around 3.00, the Rockies wouldn’t think of making him the rotation casualty. But he’s the most likely to falter, and if he does, it would make some sense to give him Triple-A innings if he needs them and the Rockies need room in the rotation.

Six-man rotation

If everyone’s pitching well when Gray returns, why bump anyone? Why not just roll with a six-man rotation? This option has some initial appeal. It would provide for additional rest for starters while also managing innings load for the rookies. On the surface, this strategy would seem to help keep starters fresh. But there’s no evidence that it would come with health or performance benefits unless at least one of the pitchers is rehabilitating from a serious arm injury. A six-man rotation probably wouldn’t benefit the Rockies in any way. It would be more likely to hurt them.

If the Rockies wanted to deploy a six-man rotation in a strict sense—starters one through six start games one through six this week and then do it again next week, in order—they should not do it. The reason is simple: it would mean Jon Gray starts fewer games. Gray is the Rockies’ best pitcher, and any strategy that results in him pitching less is failed from the start.

There’s an alternative method though. In 2015, Russell Carleton wrote a fantastic article for Fox Sports, wherein he proposed an alternative six-man rotation. In order to ensure that the team’s best pitchers play as much as possible, he proposes having the team’s top three starters pitch every fifth day instead of every fifth game. The remaining three pitchers would then combine to be starters and swingmen for the other games. For example, assuming Gray returns right on June 1, a six-man rotation might look like this:

June 1 (Thursday): Gray

June 2 (Friday): Anderson

June 3 (Saturday): Freeland

June 4 (Sunday): Chatwood (Senzatela and Márquez in the bullpen)

June 5 (Monday): Off

June 6 (Tuesday): Gray

June 7 (Wednesday): Anderson

June 8 (Thursday): Freeland

June 9 (Friday): Chatwood

June 10 (Saturday): Senzatela/Márquez

June 11 (Sunday): Gray

Et cetera

But as Project 5,183 reminds us, these sorts of rotation experiments rely on the right personnel. The best argument against this set-up for the Rockies is that Márquez is too good to hide in this role. If that’s the case, the Rockies would be better served to simply go with a five-man rotation and move one of the starters to the bullpen to replace the pitcher we’ll just refer to as Lordan Jyles.

Send someone to the bullpen

And in that case, the player to send to the bullpen is probably Senzatela. Gray, Anderson, and Chatwood won’t lose their rotation spots unless there’s another injury or one of the Tylers becomes grossly ineffective. Freeland has been the best of the three rookies in the rotation, and Márquez has the best raw stuff and the highest chance of going out and dominating.

Senzatela has been good, although he’s been walking a tightrope. Not only that, but he might have the strictest innings limit. Márquez pitched 1862⁄ 3 innings last year, so he shouldn’t run into one. Senzatela, on the other hand, threw just 342⁄ 3 innings in 2016, though he did pitch 154 the year before. This is not a judgment on Senzatela. He could prove to be an immensely valuable asset out of the bullpen—a right-handed Chris Rusin.

★ ★ ★

We’re still at least couple of weeks away before it becomes an immediate question, but right now moving Senzatela to the bullpen seems the most likely option when Gray returns. But if Senzatela continues to produce the same results he has so far, and Márquez is still an all or nothing starter, Márquez could be optioned to make room for Gray. The only one of the scenarios that seems highly unlikely is the six-man rotation, unless the Rockies think limiting Gray’s starts will contribute to his recovery. But if that’s the case, he should probably just stay sidelined until he’s fully ready to come back.

Of course, there’s another factor that would make the Rockies’ decision making smoother. It could sort itself out because of injury or ineffectiveness. This is baseball, after all, and these tricky decisions might not seem so difficult later on (they could also be more difficult, but that falls under the “good problem” area).

Finally, keep this article in mind if Chad Bettis returns this season (he might be ready in July), in which case the Rockies will have to do it all over again.