I can obtain either Tyler Skaggs or Christian Yelich in my keeper league via trade (would only be giving up a draft slot to get one of them) to stash on my minor league roster. Which one would be the choice?

FYI, scoring categories for our league MLB roster is as follows:

R, HR, RBI, SB, Errors, AVE, OPS

W, Sv, K, WHIP, ERA

Offense has more scoring categories so I think I know where to go with this one in terms of stashing prospects for later use, but wanted to get some opinions out there. Thanks guys for any input.