Wood is in the midst of a rollercoaster season, which started with winning the fifth starter job out of camp, excelling in his first four starts (3.04 ERA/3.30/3.27 xFIP) and struggling in his next four (10.13 ERA/8.12 FIP/4.50 xFIP) which led to a mid-May demotion to the bullpen.
His early season woes seemed to be a distant memory since being assigned to the bullpen before Wednesday night’s clunker.
Entering Wednesday, Wood pitched 35.1 innings and faced 143 batters since being moved to the bullpen. He fanned 42 and walked 17, which was good enough for a solid 29.37 percent strikeout rate, even if it came with a not-so-pretty 11.89 percent walk rate.
Further, Wood had limited batters to a .198/.294/.286/.579 slash line and a .289 BABIP in relief en route to pitching to a 3.06 ERA/2.52 FIP/3.52 xFIP.
The stretch of quality relief outings which ended on Wednesday had represented a noticeable improvement from his brief run as a starter this season where he faced 160 batters who slashed .259/.308/.483/.791 with a .290 BABIP in 37 innings of work, resulting in a 5.59 ERA/5.04 FIP/3.71 xFIP.
It appeared as if the key to his bullpen resurgence was in his fastball.
Since making his relief debut on May 16, Wood’s fastball — which he had thrown at a 59 percent rate out of the pen — was worth a remarkable 7.5 runs saved, per Fangraphs. That represents a significant improvement from the 1.2 wFB he had when it was used 60 percent of the time during his time as a starter.
Also notable was the increase in velocity as it had averaged 90.8 mph in relief use after clocking in at around 88.8 mph during his time as a starter.
Wood has worked primarily in low (176 batters faced) and medium leverage (108 batters faced) situations. And pitched well. His numbers in high-leverage situations before Wednesday (.529 opponents average, .824 slugging percentage, .588 wOBA) weren’t pretty and didn’t get any better with Wednesday’s showing.
Still, finding a slot for an improved Wood could help stabilize an important segment of the bullpen down the stretch.