The 2016 Yankees rotation hasn't been very good, but it is clear that Luis Severino and Michael Pineda are the weak links, with Nathan Eovaldi not too far off. Both pitchers have an ERA north of 6.00, and Pineda has a FIP over 5.00, making things pretty bad for him. The beat writers have been wondering whether or not Severino should be sent down to the minors in order for him to fix what's wrong, but that would leave the team with Ivan Nova as the only viable replacement–and that can't happen.
To put it simply, I don't trust Nova. He has a 5.14 ERA with a 3.64 FIP despite only a 4.50 K/9 over a mostly-meaningless 14 innings. The last time Nova was any good was back in 2013 when he had a great month after returning from an injury. After that, he required Tommy John surgery in 2014, was still recovering when he returned in 2015, and is now the long man out of the bullpen. It's one thing to ask him to pitch three innings on occasion, or even a spot start a few times a year, but if the Yankees remove a pitcher from the rotation, Nova is not the long-term solution.
Nova is a ground ball pitcher, and right now his ground ball rates are at a career high of 66%, but that's not going to last. He's throwing 47.8% of his pitches in the zone, which is nearly 6% higher than his career average, and he's also getting 9% more swings at pitches in the zone than he normally does. Since he returned in 2015, Nova has used his two-seamer as his primary fastball, and admittedly it's been effective so far. He's missing more bats, but not inducing any extra contact that he needs to thrive on. In fact, his contact rate is the lowest it's been in three years (which isn't really saying that much). There are interesting things going on, but the results are just not there, and given Nova's track record, it might be time to realize that they just might never be.
If he is the only choice, the team is better off taking their chances with Severino or Pineda, who have a much higher ceiling than Nova does. Both pitchers have great stuff–Severino throws hard and Pineda has great control–the problem is that neither of them have very good command, often throwing bad strikes into the heart of the zone that get pummeled. They each have good things going for them, but removing them from the rotation won't help them figure it out. Severino especially has gotten away on velocity alone during his minor league career and sending him down won't help him against the advanced hitters he is struggling against in the majors.
If the Yankees decide to go with someone else–if they have to–they are going to run into some trouble. Adam Warren is gone, Bryan Mitchell is hurt, and the depth they brought in for spring training offers very little. If they are in need of someone new, it might come down to the prospects they traded for during the offseason. After breaking camp with the team, Luis Cessa has returned to the minors to pitch a 3.86 ERA and 4.74 FIP in 16.1 innings, while Chad Green has been impressive with a 1.45 ERA and 2.47 FIP in 31 innings–averaging just over five innings a start. There is also Ron Herrera, who recently earned some press after pitching in a combined no-hitter, and had a 2.36 ERA and 3.20 FIP with a 8.44 K/9 over 26.2 innings in Double-A before getting a promotion to Scranton.
It's obviously slim pickings in the organization when it comes to starting pitching. Their depth is gone, and some of the more promising pitchers are at least another year away. The lack of alternatives could mean that they need to start considering a trade this summer, if–big if–they're still in contention by then. If not, we just might get stuck with Ivan Nova because at that point it wouldn't really matter who played.