What's wrong with Luis Severino?

If it's not panic mode yet with Luis Severino, it's certainly approaching that. While his struggles may be magnified given the Yankees poor play as of late, there's something going wrong for the young ace lately. Through 18 starts this season, Severino was brilliant, pitching to a 1.98 ERA through his 6.2 innings of shutout ball against Boston on July 1.

But in the last four starts? Well, see for yourself.

2018 Pitching Game Log Rk Date Opp Rslt Inngs IP H ER BB SO HR HBP ERA Pit Str StL StS GB FB LD PU 2B 3B IBB GDP 19 Jul 7 TOR W,8-5 GS-5 5.0 5 3 2 5 2 0 2.12 97 70 19 8 5 9 3 1 0 0 0 1 20 Jul 12 CLE W,7-4 GS-5 5.0 9 4 1 1 2 0 2.31 94 63 12 3 6 14 10 0 1 0 0 1 21 Jul 23 TBR L,6-7 GS-6 5.0 11 6 0 8 2 0 2.63 96 71 16 17 6 12 6 1 2 0 0 0 22 Jul 28(1) KCR L,5-10 GS-5 4.1 8 6 1 5 1 1 2.94 95 62 14 11 6 9 5 1 3 0 0 0

Totals 18-4 137.2 116 45 33 157 13 4 2.94 2173 68% 19% 12% 0.79 27% 8% 21 2 0 12

Provided by Baseball-Reference.com: View Original Table

In total Severino has coughed up 19 earned runs across his last 19.1 innings. So what exactly's going on?

Well for starters, he's getting fewer swings and misses in his last four starts. Outside of the swing-happy Rays, Severino caused just eight, three, and 11 swinging strikes in the three other starts. Typically he sits in the mid-teens for swinging strikes, with only three other starts seeing swinging strikes dip into the single digits, and then only as low as seven.

Perhaps velocity is playing a small role. Based on the chart below, Severino's average fastball velocity is down just slightly, though not at an obviously alarming rate. It doesn't seem like he's wearing down, and we're only just hitting August.

He's also giving up more home runs. Severino's given up seven home runs over his last four starts, compared to just six home runs in his first 18 starts. That fact starts to make more sense when you look at the trends of hard contact rate.

Here you'll see that opponents are making harder contact against Severino, especially in the last few games. Unfortunately for him and the Yankees, this trend is a larger one since the start of the season. His hard hit percentage is up while his soft and medium percentages are dropping.

The strange part is that these starts haven't all been against heavy hitters. Toronto, Tampa Bay, and Kansas City aren't offensive powerhouses. Hopefully, the Yankees and Severino can chalk this up to simply a bad stretch.

If this team is going to contend for the division and make a deep run into the playoffs, Luis Severino is an absolute key to that.