Who Exactly is Joselito Hernandez?
Hernandez was our 5th round draft pick way back in 2055 (didn't realize that was 7 seasons ago until now). I have a policy where I like to draft at least 1 catcher per draft so that I keep the minor league system filled with decent catchers. It's just something I like to do. He had some solid defensive metrics and when I took him I thought worst case scenario he'd make a good backup catcher. In the 5th round that's a same pick.
Why is he starting for the Jimmies?
Hernandez is starting for us because Tokimasa Yano broke his knee cap on a late night television show. I've got intel that one of the @breum or @Bob Breum may have paid off a staff member to cause the injury, but haven't been able to prove anything yet. I have some grainy footage of them shortly after the incident occured as seen below.

At this point the league leadership hasn't been able to decipher if there was intent or if they were just celebrating us losing a key player

How does Hernandez have a 0.8 WAR in 26 games so far?
He currently an 81 OPS+ which would rank 4th in the Johnson League if he had enough at bats to qualify for placement. He's been solid defensively with a 0.5 ZR and 3.9 Frame Rate. The defensive stats are what I'm assuming has bumped his WAR rate up this year. Early in the season though so lots can happen.
Why didn't Charm City bring up Edgardo Reyes to replace Yano?
We didn't bring Reyes up because we felt he still had somethings to work on in AAA (we're trying to avoid super 2 status). We feel very confident about Reyes and believe he'll be the catcher of the future for our organization behind the plate.
Final Thoughts
I basically did this writeup to give some light to a former 5th round selection who I'm happy to have seen develop into a servicable catcher. For every Dave Ackerman or Kazunari Chikafuji it can often be the depth players who can rescue your season because injuries happen over the course of 162 games and if you're going from an All Star to a journey man minor league backup you're going to probably lose more games than you win over the course of the season.
To be honest I'm at a bit of a crossroads with Yano right now. He's on a player option for 12 million next year. If he executes his option as I expect I think we're going to just cut him to save the cap space as we head into 2063. My initial plan was to bring Reyes up around mid June and have him split time behind the plate for the rest of the season. Now I'm expecting to promote Reyes and a few other players to the active roster sometime in early to mid June and have Reyes get the bulk of the reps at catcher. Unless Hernandez plays lights out baseball I'm expecting him to slide back to the backup catcher role and have Reyes become our starting catcher for the rest of the year and the long term. Anything can happen though in the BBA so nothing is set in stone as they say.