I’ve wanted to do a post on Carlos Martinez for a while, and as I was looking at batted ball statistics at Fangraphs I noticed he’s currently eighth in ground ball rate at 55.6 percent, an increase from his two previous seasons. There were other names that caught my eye, too, so I thought I’d take a look at a few pitchers who’ve increased their ground ball rates and what that means for their rest-of-season outlooks.

In 117.2 innings over 2013-2014 Martinez posted a 51.5 percent ground ball rate, which is stellar in its own right. Most of that was in relief appearances, thought, so it was fair to wonder whether he’d be able to improve on it as a full-time starter. Through 17 starts in 2015 he has improved to that 55 percent mentioned above, which has helped him to a 2.70 ERA, 3.57 FIP and 3.17 xFIP. Martinez ranks 16th among qualified starters in ERA, and he’s one of only five starters to have an ERA below 2.70 with a strikeout rate above a batter an inning. Prior to this year Martinez had a 21.2 percent strikeout rate and 8.8 percent walk rate. So far this year he has raised his walk rate one percentage point, but to balance out that he’s raised his strikeout rate four percentage points and from 8.45 per nine to 9.45 per nine. He’s kept his walk rate per nine at 3.6. His home run rate has more than doubled, but only to 0.9 per nine. That can be expected as he sees batters multiple times throughout the game so I’m not worrying about that.

As a Cardinals fan I’ve seen most of Martinez’s starts and the tape doesn’t lie: his changeup is his best pitch – in whiff per swing rate and in opponents’ batting average. The good thing is he’s started throwing it more than ever before, up from 9 percent last year to 18 percent this year. Another adjustment Martinez has made is he’s throwing his four-seam fastball less often, from 51 and 43 percent, respectively, the last two years to 32 percent this year (you can see that in the most previous link). That’s good because in his career he’s allowed more walks than strikeouts on the pitch and hitters hit .323 on the four-seamer with a .504 slugging against it. He’s also using his sinker 25 percent of the time, which is more often than he did in the past. He’s only allowed two extra-base hits off of it this year – both doubles – and it’s induced ground balls over 66 percent of the time it’s put into play. Most likely Martinez won’t maintain a sub-3.00 ERA the rest of the year, but with the increase in changeup and sinker usage he shouldn’t see it rise higher than his 3.17 xFIP – especially once his home-run per fly ball rate of 15 percent comes down.

Brett Anderson leads the league in ground ball percentage at 68.4 percent, which is almost five percentage points higher than Dallas Keuchel’s second-place number. His 3.00 ERA ranks 24th among qualified starters, and his 96 innings in 2015 are already the most he’s thrown in any season since 2010. Anderson’s velocity has decreased throughout his career, but not by too much, and he hasn’t undergone some crazy transformation that’s never-before-seen. But he has dropped his four-seamer usage from 50 percent as a rookie gradually every year but one since 2009 all the way to 22 percent this year, while upping his sinker rate every year save one from 2 percent in 2009 to 28 percent this year. The sinker leads to a ground ball 81 percent of the time it’s put in play, and Anderson’s kept his slider usage steady this year (27 percent) and that pitch leads to a ground ball almost 71 percent of the time, according to Brooks Baseball.

This year he’s only given up four extra-base hits on the sinker despite it being his most-used pitch, and his slider – his second most-used pitch – has only been hit for extra bases five times. Anderson’s always been skilled; he’s always been injured, too. But you don’t get a career ERA/xFIP/FIP trio all within 3.49-3.62 (mostly in the AL) without being a good pitcher. It seems like as long as he can stay healthy this year he’s found a way to be very successful.

Gio Gonzalez hasn’t experienced a fruitful 2015 season on the surface, but several underlying stats say he should be able to turn his season around. He sits at sixth in ground ball rate at 56.5 percent, which is a career-high by seven percentage points. What’s also a career high is his 4.16 ERA. But while in his five full seasons Gonzalez has always posted an ERA similar to his FIP and xFIP he isn’t this season, as those numbers are 3.16 and 3.47. Gonzalez’s home run rates and left on base rate are right around his career numbers, and his strikeout rate minus walk rate of 11.9 percent is only one percentage point below his career mark. The sore thumb is his .345 average on balls in play, which is 53 points higher than his career mark. My first thought was to blame his defense, but this is pretty much the same defense he’s had since he’s been in Washington.

Like the aforementioned pitchers Gonzalez is throwing a career-high number of sinkers and a career-low number of straight fastballs. But he hasn’t seen the same success. This season hitters have a .341 average and .481 slugging against his sinker. But that’s started to change. In the first two months of the season hitters had a .379 BABIP overall against Gonzalez and he had a 4.73 ERA. But since June 1 Gonzalez, who’s still thrown his sinker over 40 percent of the time, has a 3.03 ERA thanks to a .279 BABIP. Since June 1 Gonzalez has been able to limit the damage on his sinker to only one extra-base hit. I think it took Gonzalez a while to get comfortable throwing a sinker as his main pitch and combined with bad luck that kept him from getting off to a good start. But it does seem he’s turned a corner, and even though he doesn’t have as stellar a strikeout rate as usual he should be able to put up good stats as long as he continues the continued use of the improved sinker.