The Dodgers traded for Yonny Hernandez in the offseason and slapped him on the 40-man roster. Though he has two minor-league options left, he may not be worth a 40-man spot if the Dodgers are seriously attempting to upgrade their infield after Gavin Lux tore his ACL and MCL.
The only issue is that Hernandez is quite literally the backup third baseman (per the depth chart). That could change if the Dodgers make Miguel Vargas the backup and then shift around Miguel Rojas/Chris Taylor/Mookie Betts at second base and shortstop, but that isn't exactly "depth" -- it's versatility. That's not a bad thing, but the Dodgers might not view it as advantageous to keep moving around their most important players like that.
Hernandez has had a solid spring (.273 AVG., .769 OPS, 2 HR, 1 3B), but the Dodgers might be better off searching for a superior backup option, since it'll be much more difficult to do so at second base and shortstop. After Michael Busch was optioned, that could very well accelerate such a plan.
Also, we're just not sure a 24-year-old with limited MLB experience and a less-than-impressive track record at Triple-A is worth a roster spot, given the Dodgers' current situation.