When Alex Cobb was a prospect coming up through the ranks in the Tampa Bay minor league system he was never considered all that highly. Noted prospect hound John Sickels ranked Cobb 17th in the Tampa Bay system, behind luminaries like Aneury Rodriguez, Kyle Lobstein, Wilking Rodriguez, and Alexander Colome. Sure, there was some potential back-of-the-rotation starter sheen there, but nobody was touting the righty as a future staff ace. Even when Cobb arrived in the big leagues he was still somewhat of an afterthought struggling to stay in the rotation before grabbing the 5th spot in the rotation this past spring.

Well, here we are in June and it’s Cobb who’s having the last laugh. After toying with a potent Tigers lineup on Wednesday, Cobb’s ERA now sits at 2.39, good for 3rd best in the American League. Cobb’s striking out a career best 8.24 hitters per 9, and his walk rate is down to a career low as well. More importantly, Tampa Bay is now 8-3 in games started by the 25-year-old righty, which has allowed the Rays to remain competitive despite the struggles of 2012 Cy Young winner David Price and the departure of longtime staff leader James Shields. So how has Cobb been able to go from seldom-discussed 5th starter to one of the most dominant pitchers in the American League?

Well, according to Cobb, a big part of his success is owed to his shiny, new curveball. Cobb decided to alter his traditional curveball grip around midseason a year ago, discarding it in favor of a harder, spiked grip curve practiced by former Rays starter James Shields. “It keeps a tighter spin,” Cobb said. “More of a four-seam rotation so it’s harder to pick up. I’ve also gained a few miles per hour on it, so it’s been a huge help this year.” After a bit of tinkering he immediately noticed a difference in his performance.

“It’s huge,” Cobb said. “Not only for a put-away pitch but it’s also, on the change-up I relied a lot on swings and misses hoping they chase out of the zone. This curveball allows me to start off the count early with just a get-me-over curveball, and usually they’ll take it if it’s not the pitch they’re looking for. So to be able to get ahead in the count is huge. I wasn’t able to do that so much with my change-up. It’s more of a hoping they chase kind of a pitch, and this one is more of an out of the zone in the zone.”

The data backs Cobb’s assertion as well. From his call-up day in the middle of May through the end of July, Cobb threw his breaker just 14% of the time. Cobb also wasn’t very accurate with the pitch, throwing it for a ball 46% of the time which meant hitters could lay off. Since the rest of Cobb’s repertoire (4-seamer, sinker, splitter) all average at least 85 miles per hour, he was predictable and the results were predictably poor. His record over during his starts from May through the end of July: 4-8 with a 4.93 ERA and a .283 opponent’s batting average.

But something happened in August of 2012. A light bulb went on in Alex Cobb’s brain and he started to use his new-found curveball to devastating degree. From August 1st through end of the season Cobb threw the curve nearly 25% of the time and his season really turned around. In his August 1st start against the powerful Oakland A’s, Cobb threw 18 curveballs (18.9% of his pitches on the day were curves), his highest total on the season up to that point, and the bulb in his brain was burning bright. His next outing, against the Toronto Blue Jays, Cobb dealt up 26 curves (25.5 % of his pitches were curves) and he hasn’t looked back since. His record from August 1st onward was an impressive 7-1, his ERA was a very solid 3.09 and his opponent’s batting average had dropped nearly 60 points.

Those positive trends have only continued in 2013 for Cobb. He’s throwing his curveball nearly a quarter of the time (23.4%) and the overall results have even blown reigning greatest hitter in the universe, Miguel Cabrera, away. Cobb has been fooling hitters for most of the year by starting them off with his breaking ball (35% of all his at-bats start with a curve), before going in for the kill with his devastating splitter. This gets the hitter thinking about one type of movement and spin and it makes it that much more difficult to pick up another different type of spin, movement and drop.

By working these two pitches together seamlessly Cobb’s been blowing the league away. As soon as he gets 2 strikes Cobb’s been angling the splitter down low on hitters, generating a swing-and-miss rate of 24%, which is phenomenal and leads to nights like this one against the Padres. If Cobb can continue to mix and match his pitches this well he should become the latest All-Star success story to come straight from the farm in Tampa Bay.

Thanks to Brooks-Baseball.net and Baseball-Reference for the statistical help.