Hosmer has been very inconsistent over the last years. But what can it be attributed to? His plate discipline is pretty fine as he is having a single digit K-BB% rate (league average 14%). Also his Max EV is above average at 112 as is his average EV.
The issue is obviously the angle he is hitting the balls at and that is no secret of course. His average Launch angle is just 3.5 degrees while the league average is 12.5. But it doesn’t stop there, his LA actually gets worse when you look at low pitches (0) or pulled balls (-4) or the worst pulled and low (-6). That means he basically can’t effectively hit anything inside or anything low which is a huge problem for his power output.
Now obviously he could adjust by never swinging at anything low or inside and short term that is probably what he should do but long term that is not a viable strategy first because pitchers will adjust leading to a too high called strike percentage and second and second because pulled balls tend to yield a higher power output.
So to get back on track with consistency and not just hope for some babip and HR/FB luck like he did in some of his good years he needs to cover the zone better and be able to drive the ball in the air in all 4 corners of the zone. He doesn’t have to be an extreme FB guy but he should be able to hit middle range line drive balls (15-20 degrees) all over the zone gap to gap. I wouldn’t try to make him a pull hitter but at least he must be able to hit high liners to the pull gap consistently.
Hosmer did state in interviews that he did try to work on stuff to increase his LA so of course he is aware however changes in that direction if they happened at all were only short lived.
So let’s look at his movements a little. IMO the issue he has is not a too bad attack angle. It is a bit on the flat side but it isn’t really negative and other guys do have success with flat-ish swings, for example Stanton, Vlad jr and soto who have flatter swings and still have decent launch angles.
yeah his AA probably should be a few degrees higher but it certainly is not explaining outrageously low launch angles.
There are two other really big issues that I see.
The first one is his posture on lower pitches. If you compare him to trout trout has almost twice as much side bend on a pitch in the lower third as hosmer has
trouts bat isn’t really pointing down either
but is pretty parallel to the top of his shoulders but due to his side bend he has a much steeper vertical bat angle. This bat angle means that he is not topspinning low balls but staying through them and hitting them straight.
This posture issue leads to a too flat vertical bat angle on lower pitches and thus roll overs which is explained here
To work on side bend here are some drills
First work on isolating forward bend to side bend transition
then do some thoracic flexibility work
and some dry posture turns
and then some drills to integrate into the swing
There are also devices like the “Quant tee” which can help to force a steeper VBA but I think first the posture issue should be fixed.
The second issue I see is some instability in both his lower and upper body.
here you can see that his spine angle isn’t really super consistent and the legs aren’t super stable either. This can affect barrel accuracy and cause an inconsistent VBA through the zone.
I would recommend here some work on decel and anti rotation like for example stop swings
half swings which is basically swinging the arms to extension after contact that then swing the extended arms about a foot or two without rolling over (arms can re-flex a little but should stay mostly extended)
med ball Decel (first drill in video)
and for the front leg this drill
Those stability and posture issues should already help him on the inside pitch too because it helps him to create space but additionally he could also do the good old cano drill and work on hitting inside pitches in the air with that drill
and maybe as a movement preparation this drill
Those are only a few suggestions and there is more stuff you can do but I think I could outline why it probably wasn’t so easy for him to make a change and just hit the ball higher. Some people in the media questioned his willingness to change but I seriously doubt that someone in 2021 is not knowing the value of proper launch angle after thousands of statcast batted ball events and every mlb team having an analytics department. But I think with a few changes to his movement with very focused training in the offseason he can make the change and become a productive MLB hitter for the next years.