News flash: Desmond Jennings has struggled mightily this season. He's struck out in a quarter of his plate appearances. His ISO is down nearly 100 points from his career average and his wRC+ is a meager 28. To be fair, Jennings has never been an elite hitter, at least not over the course of a full season. Much of his value has come from his defense and base running.
Jennings 2016 Offense
Still, Jennings's numbers are well off his career averages and pre-season projections. Perhaps some of Jennings' struggles can be blamed on his .210 BABIP, but his contact and swing rate stats suggest there's more to his troubles than mere bad luck.
All data below were taken from Fangraphs:
Jennings is swinging at the highest rate of his career. A high proportion of these swings have been at pitches outside the strike zone, and Jennings is making contact with pitches outside the strike zone at the highest rate of his career. This probably explains some of his weak contact. But Jennings's contact rate on pitches inside the strike zone has dropped by nearly 10%, and that's worrisome.
Guyer 2016 Offense
As disappointing as Jennings has been, Brandon Guyer's start has been equally exciting. The knock on Guyer, a former fifth round draft pick who came over from the Cubs in the Matt Garza trade, has always been that he was a platoon player whose minor league power never carried over to the majors. But he's starting to shed those labels.
Since the beginning of the 2015 season, Brandon Guyer has amassed 457 plate appearances. Over that period, he's put together a .277/.377/.428 triple slash, with a .357 wOBA, and a 132 wRC+ line. He's always been able to mash lefties, but he's become an above-average hitter against right-handed pitching too.
Guyer has shown flashes of the power he displayed in the minors leagues in 2011-12, and is beginning to put it together more consistently. He had shoulder surgery in 2012, and believes the operation prevented him for hitting for power for a couple years following.
Much like Liam Neeson in Taken, Guyer wields a very particular and very interesting set of skills. Whereas most humans would reflexively move out of the way if an object hurled at 95 mph were headed toward them, Guyer doesn't flinch.
As a result, many pitches seem to find him. His hit-by-pitch ability is so renowned, there's even a Twitter account following his assault on the single season hit-by-pitch record.
Guyer has gotten hit by pitches in 15% of his plate appearances this season, and he's tied for first for the most hit-by-pitches since the start of 2015 (35). The man he's tied with, Anthony Rizzo, has nearly twice as many plate appearances as Guyer over that period.
This isn't insignificant. Guyer's ability to get hit by pitches gets him on base, sure. But equally important, it forces opposing pitchers to choose between the odds of drilling him if they throw inside or leaving hittable pitches out over the middle of the plate. It's a win-win for Guyer (assuming he doesn't get injured) and the Rays.
Guyer rates as a solid defender, and potentially a very good one. In left field, he has a career 6.3 UZR that rates as a 10.4 if he were to start 150 games. In fact, his career UZR is positive across all three outfield spots. He's a good baserunner too. The Rays don't run much, but he stole 10 bases last season, and contributed five runs on the base paths in 2014.
Who's in Left?
Guyer's emergence makes Jennings expendable. There was talk that one of the two was likely to be traded before the season, but presumably no trade partners were found.
With Mikie Mahtook and Taylor Motter stashed away in the minors, Jennings could be dangled as trade bait. In his age-29 season, Jennings would likely need to prove his health and show a rebound in production for the Rays to get anything of significance for him. This is particularly true for the type of player Jennings is; the areas he's always provided value - defense and baserunning - don't project well for players who have a history of knee problems and many innings logged on the Tropicana turf.
Guyer probably won't be as good the rest of the way as he's been so far this season. His .432 wOBA is inflated by a likely unsustainable hit-by-pitch rate and a .400 BABIP. And Jennings probably won't be as bad as he's been. But even if Guyer can be a .330-.340 wOBA player, he'll represent an upgrade over Jennings in left field.
Don't look now, but Brandon Guyer is forcing his way into the Rays everyday lineup.