Madison Bumgarner could be the prize of the starting pitching trade market. But he's also one of the bigger uncertainties. The real question looming: Can he still be classic playoff Bumgarner for a contender in 2019?

The Giants' longtime ace hasn't been to the postseason in a few years; in those seasons since, he's been hurt and sometimes ineffective. But those postseasons … Bumgarner's long track record of October dominance has to be enticing to Trade Deadline buyers, and he seems like he's proved himself over the first half of 2019.

So what's the answer? There are real reasons to think that Bumgarner can be a force for a playoff team. There are also a few lingering concerns. Let's look at the numbers.

THE GOOD SIGNS

His strikeouts are up

Bumgarner has struck out 121 batters in 116 2/3 innings this season. He hasn't K'd more than a batter per inning since 2016, his last All-Star season, when he punched out 251 in 226 2/3 innings. He's got a chance to break the 200-strikeout mark again.

Bumgarner's 24.9% strikeout rate this season is his highest since 2015, after it dipped under 20% in 2018 for the first time since his first full big league season as a 20-year-old in 2010. He's cut his walk rate, too, from 7.8% to 5.1%, giving him about a 20% differential between his strikeouts and walks that's his best since '16.

The takeaway is this: Bumgarner's strikeout numbers this year look more like they did in his dominant 2013-16 run than they did in his injury-marred years in 2017-18, or even in his early-career years from 2010-12.

He's regained velocity

Bumgarner's four-seam fastball velocity this season is the highest it's been since 2015. It's not like he's a fireballer -- his average velo is 91.6 mph -- but he's still reversed a three-year negative trend. And a little more jump on the heater can't hurt.

From 2015-18, Bumgarner's fastball velocity declined steadily, from 92.7 mph to 91.2 mph to 91.1 mph to 90.8 mph (the same issue that rival Clayton Kershaw has dealt with). This year, he's gained almost a full mph back. So maybe it's no coincidence that he's throwing his four-seam over 10% more often than last season (44.3% usage vs. 32.4% in '18).

He's added spin

A lot of spin, actually. Bumgarner's spin rate has jumped by more than 300 rpm on each of those three chief pitches in his arsenal: the four-seamer, cutter and curve. He's gone from below-average to above-average spin on each pitch type, and their spin rates are all at their highest of any season under Statcast tracking.

Bumgarner's spin rate increase, 2018-19
4-seamer: 2,082 to 2,390 rpm ... +308 rpm (MLB avg.: 2,285)
Cutter: 2,129 to 2,473 rpm ... +344 rpm (MLB avg.: 2,354)
Curveball: 2,297 to 2,625 rpm ... +328 rpm (MLB avg.: 2,524)

That spin, in particular, has turned into more horizontal break on his curveball and a little extra rise on his fastball. Bumgarner's curve is breaking about three inches more than it did last year, and it's gone from slightly below average horizontal movement to +2.1 inches above average. And while Bumgarner has never thrown the riseball of a Justin Verlander type, he is getting about two more inches of "rise" (i.e. less drop) on his four-seamer than he did in 2018.

In kind, Bumgarner's swing-and-miss rate has jumped on all three pitch types: 12.8% to 21.4% on his four-seamer, 24.9% to 27.4% on his cutter and 27.4% to 33.9% on his curve.

He's getting chases and whiffs

Last season, Bumgarner's chase rate induced -- as in, how often hitters swung at his pitches outside the strike zone -- dropped to a career-low 26.3%. This season, it's up to 32.3%, the second-highest of his career, just a sliver off his career best of 32.4% in 2015.

He's inducing more chases than over 80% of the league. And it's helped his strikeouts, as a little over half of Bumgarner's K's have come on chased pitches, his highest proportion since that 2015 season. When you chase, you miss. Hitters are whiffing on about a quarter of their swings against Bumgarner this year, the highest swing-and-miss rate he's generated since '16.

Chalk it up to more precise location on the four-seamer/cutter/curveball troika. Bumgarner's tightened up his fastball spots, and he's putting his curve and cutter around the corner more than ever.

THE CONCERNS

It's not all dominance, of course. Bumgarner's 3.86 ERA isn't sparkling, and there are some real reasons why. Here's what teams will have to think about as they weigh trading for Bumgarner:

His hard-hit numbers are shaky: Bumgarner has allowed a 41.5% hard-hit rate this season -- that's the percentage of batted balls against him that are hit 95 mph or harder. It's actually his highest hard-hit rate allowed since Statcast started tracking exit velocity in 2015, and it's one of the higher hard-hit rates in the league among regular starters.

Too many air balls: Bumgarner's always been more of a fly ball pitcher, but his ground-ball rate is still the lowest it's ever been, at just 38.3%. For the first time in his career, over half the batted balls he's allowing are fly balls or line drives -- 54.5% -- and those are the types of contact that can do damage.

His quality of contact allowed is not great: Statcast sums up a pitcher's overall numbers with a stat called expected wOBA, which considers his strikeouts, walks and quality of contact allowed based on exit velocity and launch angle. League average expected wOBA this season is .321. Bumgarner's expected wOBA allowed is .330.

The hard-hit balls, line drives and fly balls allowed play a large part in that. They're issues Bumgarner will look to correct in the second half, to set up a throwback October.