I would rather have Davies then Mac (assuming he isn't miscast as the lefty in the pen next season). I don't think there is a chance in the world that Garcia will be starting in the majors next year.
I don't even view Davies as a viable member of the rotation. I just see him as a guy that can pitch at AAA and if the O's need a sport starter for a day or a month they can bring him up.
Career Para = career Snider. One they have already and the other costs as much in two months as the other does for the whole season and an emergency starter next season.
He's rocking a 370 BABIP and his career wRC+ is 95.
He's as or more likely to fall back to career norms as he is to continue at his current level.
Not too many guys become a totally different hitter their sixth year in the league.