The season has gone pretty well for the Yankees thus far. Sure, the team brought in Neil Walker and Brandon Drury in the offseason and they are currently below replacement level; however, those two were acquired as placeholders for Gleyber Torres and Miguel Andujar, and the two prospects are already succeeding in the big leagues, leaving the performance of the acquisitions moot. Greg Bird got hurt again and Tyler Austin wasn’t great. Giancarlo Stanton has only been good and not great, but Aaron Judge has been great, and Didi Gregorius and Gary Sanchez have been good while Brett Gardner and Aaron Hicks have exceeded expectations. Yankees position players lead the American League in WAR at 13 and are projected to top all of baseball the rest of the way.

On the pitching side, the Yankees have done pretty well, too. Just as they were projected, the bullpen has been the best in baseball, striking out 32% of batters faced. Luis Severino has been one of the best pitchers in baseball with a 2.15 FIP that leads all qualified starters in the American League. After Severino, the rotation hasn’t been good, but with the bullpen, the team’s 9.5 WAR is third in all of baseball.

Fortunately for the Yankees, the team’s good results have translated in the win column up to this point with 40 victories. At this moment, they are projected to win more than 100 games and finish with the best record in baseball. The Yankees may be in an enviable position; however, there are some drawbacks to being an immensely talented, super-rich franchise piling up wins like nobody’s business.

The first drawback is their main rival, the Red Sox. Boston is also an immensely talented, super-rich franchise piling up wins, and only one of these two teams is going to win the division. Despite having the two best records in baseball and the highest playoff odds in the game, the Yankees and Red Sox rank fifth and sixth, respectively, in odds of making the division series. One of the two clubs is going to have to fend for itself in the Wild Card game in what will likely be a 50/50 shot against Shohei Ohtani, James Paxton, or maybe even Justin Verlander. Winning the division is going to affect the Yankees’ odds of winning the World Series by 5%-10%, maybe more.

Because the Yankees and Red Sox are both playing at a very high level, should one team slip a bit, the other will likely take advantage. Likewise, if one team could improve by just a win or two, their chances of success in the playoffs would improve considerably. That leads directly to where the Yankees are most likely to slip or improve, which is the rotation. This is what the Yankees’ projected rotation looked like at the beginning of the season.

Luis Severino was expected to put up another ace-like performance, Sonny Gray and Masahiro Tanaka were supposed to be above average, Jordan Montgomery was supposed to build on a solid 2017 with another decent season, and CC Sabathia was supposed to fill in some innings at an adequate level. The depth didn’t look great, with only Domingo German even approaching average. Two months into the season, this is the performance the team has received from its starters.

Yankees Starting-Pitching Performance Name GS IP K/9 BB/9 HR/9 ERA FIP WAR Luis Severino 13 86.0 10.67 2.2 0.42 2.20 2.15 3.2 CC Sabathia 11 57.2 6.87 2.34 1.56 3.59 4.73 0.6 Sonny Gray 12 63.2 8.20 4.24 0.99 4.81 4.32 0.8 Jordan Montgomery 6 27.1 7.57 3.95 0.99 3.62 4.17 0.5 Masahiro Tanaka 12 67.2 8.65 2.39 2 4.79 5.05 0.4 Domingo German 5 27.0 8.67 4.0 1.33 6.33 4.67 0.2 Total 58 329.1 8.69 2.95 1.2 3.94 3.99 5.6

So far so good, overall — thanks largely to Severino’s brilliance. Sabathia has pitched as expected, but after that, it doesn’t look pretty. Gray — even after last night’s encouraging start — and Tanaka have underperformed, German has already hit his projected number of innings, and Montgomery will miss the rest of the season due to Tommy John surgery. As for the rest of the season, even with improved projections for Severino and German, the loss of Montgomery and the decline in the rest of the rotation means the rest-of-season ERA and FIP are slightly worse than when the year started. If Gray and Tanaka don’t improve or one of them turns out to be injured, the Yankees are in position to lose whatever slim projected advantage they currently have over the Red Sox.

In addition to the currently hurt Cessa and the recently hurt Domingo Acevedo, the Yankees have no decent options should another rotation member get injured. Here are the projections for depth options mentioned in a YES Network piece.

This group is not without its upside. Sheffield and Abreu are decently ranked prospects, Adams had a good season in the minors last year, Swanson has merited Fringe Five status, and Stephan and Loaisiga have decent projections. However, Sheffield has walked 13% of batters faced this season, Abreu has been limited by an appendix injury and pitched poorly this year down in High-A, Adams’ Triple-A numbers aren’t very good, Loaisiga and Stephan hadn’t pitched above Low-A before the season started, and Swanson and Rogers can’t be expected to bring much to the table. If the Yankees lose another starter, their odds of winning the division, and consequently the World Series, will be diminished considerably.

It might be tempting to look at all the talent on the Yankees and think they can get by with a replacement-level fifth starter. They will probably make the playoffs if they make no moves, so it isn’t as if they have to do something to be competitive. If they want to considerably increase their odds of postseason success, however they will need to add someone — perhaps soon. If they are going to make a move now, they would need to target teams that are already out of the race.

There are always arms available, and surely some of the potential options would be a fit. Cole Hamels might be too expensive or cost more in prospects if the Yankees need Texas to pay most of the salary. Michael Fulmer might cost too much in talent. Chris Archer, J.A. Happ, and Marcus Stroman might not be available yet or at all. Perhaps Tyson Ross or Jordan Lyles of the Padres would make sense. Danny Duffy hasn’t pitched well this season. Madison Bumgarner, Jacob deGrom, and any Orioles pitcher seem far-fetched as a possibility. The trade picture is going to clear up quite a bit over the next couple months, and if the Yankees are going to win the division, they are probably going to need to make a trade for a starting pitcher.