Defensive stats are notoriously inconsistent, as you know, and the default answer is not necessarily whichever stats show him to be better at the position.
Whatever analytics the Tigers use tell them that a combination of 2B Gleyber Torres and 1B Colt Keith projects to be worth more wins, taking their combined defense and Keith's reduced offensive value at first into account, than a combination of 2B Colt and 1B Spencer Torkelson would be, considering their combined defense and Colt's elevated offensive value at second. I'm willing to give the front office the chance to prove they know what they're doing in cases like these, until they demonstrate to me that they don't.