Niese keeping opponents grounded

Jonathon Niese had a disappointing start to the season, going 1-2 with 4.79 ERA in his first eight outings. Niese injured his hamstring in his eighth start on May 16, during which he allowed five runs and failed to retire a batter in the third inning. He landed on the disabled list the next day.

Niese returned to the mound on June 5th against the Marlins and since then has pitched brilliantly. He is 5-0 with a 2.43 ERA in his last six starts, including a complete game one-hitter on June 10 vs. the Padres.

How has Niese seemingly turned around his season since returning from the disabled list, showing signs of being the future southpaw ace in the Mets rotation?

Niese is a strong groundball pitcher, with a groundball percentage of 51.2 percent that is well above the league average of 44.6 percent. However, his recent hot streak isn’t a result of him actually generating more worm-burners. In fact, his groundball percentage in his last six starts is slightly lower (50.4 percent) than in his first eight starts (51.7 percent).

The key stat for Niese in his last six starts is that opponents are hitting just .155 when putting the ball in play on the ground, with a mere nine hits in 58 at-bats ending on grounders. That’s an amazing number for Niese, considering that the league average on grounders is .231, and opponents hit .306 on his groundballs in his first eight starts this season.

Given that it’s been shown that pitchers have little control over the outcome of their batted balls in play , you could argue that Niese was simply really unlucky in his first eight starts and has been really lucky in his last six starts. However, using data from Inside Edge, we can see that Niese is actually doing a much better job of inducing weakly hit grounders in his last six starts.

In his first eight starts, 13.9 percent of groundballs hit into play were “well-hit” balls, which is above the league average of 12.9 percent. But in his last six starts, only 6.9 percent – a mere four of his 58 grounders in play – were “well-hit”.

Jonathon Niese, Groundballs

Niese also appears to be benefitting from a vastly improved infield defense in his last six starts. According to Baseball Info Solutions, in his first eight starts, the infielders combined for a plus-minus rating of minus-2.4, which means that they made two fewer plays than the average infield would have made; in his last six starts, the infield was plus-6.3, as they have combined to make six plays more than the average infield.

Jonathon Niese, Infield Plus-Minus

Niese's ability to generate weak grounders in his last six starts has really helped him limit the damage when he's pitching with runners on base. Before going on the disabled list, Niese allowed batters to hit .333 on grounders when pitching from the stretch, and 13.3 percent of those were "well-hit". Since returning from his injury, opponents have hit just .190 on his worm-burners with runners on base -- a mere four hits on 21 groundballs -- and none of those balls were "well-hit".

Tune into Wednesday Night Baseball on ESPN at 7 ET as the Mets and Niese try to shut down the Reds’ league-leading offense in the rubber game of their three-game series at Citi Field.