A no-Bull(s) Chicago rebound

Ryan Dempster's problems with the long ball were news -- of a ghastly sort, but news nonetheless -- in April. After surrendering nine homers in his first six starts, alarm klaxons where blaring, fans were panicking and an already bleak rotation picture for the Cubs after the injuries to both Randy Wells and Andrew Cashner had burrowed down to simply grim.

Dempster’s performance was appalling, but the worst element was his homers allowed. Giving up homers on nearly 6 percent of all plate appearances is difficult to sustain without earning a permission slip to try matching it someplace else -- via trade, waivers or an invitation to explore the exotic venues of the Pacific Coast League. Armando Galarraga was doing even worse than that despite pitching in another so-called year of the pitcher, and that earned the Snakes’ starter a trip to Reno earlier this month.

How ugly is a home-run rate of almost 6 percent? Only five pitchers have managed to allow homers to more than 6 percent of all opposing batters while throwing as many as 80 innings in a season, a list comprising of four pitchers from the past decade (Ezequiel Astacio in 2005, Bruce Chen in 2006, Josh Geer in 2009, and Andy Benes in 2001), but topped by Ken Dixon of the Orioles after surrendering 31 homers in 105 IP in 1987 -- in what was definitely a year of the hitter.

Dempster was allowing home runs on 16.4 percent of all fly balls in April, which was the league’s worst mark, and so far beyond his career rate of 8.0 percent or his 7.5 percent rate in the Cubs’ rotation the past three seasons that, barring an unannounced injury, it seemed unlikely to persist. The MLB leader last season was Ted Lilly, between his time with the Cubs and Dodgers. In 2010, Lilly endured a rate of seeing 10.2 percent of his fly balls become homers. Dempster finished eighth in the majors among ERA title qualifiers with a 9.2 percent HR/FB ratio. He was also walking more than 10 percent of the batters he was facing, something he hasn’t done since 2007, which was his last year in the bullpen.

Naturally, this led to speculation he might be hurt, but Dempster and the organization deflected that line of thinking. Initial concerns over his velocity may or may not have been overstated -- per PitchF/X data, he’s throwing effectively the same mix in roughly the same ratios, relying on fastballs of various stripes, a slider and a few changeups to spring on the odd lefty.

All of which is a long way toward saying that, as bad as it was in the early going, one way or another it wasn’t likely to last, and sure enough, it hasn’t. In his five turns in May, Dempster has allowed two homers in 32 innings while hurling his first four quality starts of the season. While the Mets lineup he faced on Tuesday wasn’t exactly the best slate of opposing batters -- certainly not with both Ike Davis and David Wright on the DL -- Dempster hasn’t been making a comeback against patsies, having pitched well against the Giants and Reds, not to mention a Dodgers team that a little more than a week before had clubbed him for three homers in an incomplete first inning he was mercifully removed from.

After the game, Dempster deadpanned that it was his best start of the year -- “that or Florida,” where he’d allowed five runs in five innings his last time out. His focus in his brief postgame remarks seemed less on the evening’s outcome in the 11-1 rout of the Mets than on reminding the reporters present that Randy Wells would be back from the DL in the coming weekend series against the Pirates, and that Matt Garza wouldn’t be out too long now that he’s on the DL as well. In the wake of the announcement that Cashner won’t need surgery, but will probably be out until after the All-Star break, that seems like a classic case of a veteran taking it one day at a time, but in bouncing back from a month-long train wreck, what would you expect for him to say?

Before the season, Dempster was projected for a 3.75 ERA by ZiPS and a 4.10 ERA by PECOTA. His latest five-start run has come with a HR/FB ratio below 5 percent, just six walks allowed in 32 IP and an ERA of 3.09. Not exactly dominant, but durably useful, providing a reminder that bad starts can happen to good starters. He should resume going back to being what he’s been, an innings-eater with a sense of humor, and that distinctive full-windup wiggle with his glove hand as he delivers.

Christina Kahrl covers baseball for ESPN.com. You can follow her on Twitter.