Interesting, he was an all star in the Northwoods League this summer http://northwoods.bbstats.pointstreak.com/player.html?playerid=1367841
He had TJ surgery in December 2017, is 3 years out of high school and, as stated in the link above had committed to playing for Oklahoma State next year after playing for San Joaquin Delta College, a Junior College in Stockton, CA. He evidently redshirted his Sophomore year and would have been a redshirt Junior for Oklahoma State next year. Maybe he is more than just filler. I would bet he got a pretty decent bonus to sign ($100K or more). Since the Orioles had some money left from their draft slots, they could have gone over $125K with the amount over that counting against their slot money. The rules for undrafted free agents are the same as signings after the 10th round in the draft.