Tellez's bat was elite last year - he made drastic improvements to his BB% and K% and was statistically the 51st best hitter in baseball last year with underlying advanced stats that suggest he wasn't getting 'lucky'. That's why people want to see him get consistent playing time because even if he's primarily a DH, every lineup in baseball has room to add someone with a wRC+ over 130.
You don't judge a player and banish him to the bench after 63 PA's - especially when there are several underlying stats suggesting he's hitting the ball very hard this year (which is a great predictor of success) and has been unlucky).
Perhaps they see something in his swing this year that needs adjustment and time at the alternative site could be the place to fix that. However, I suspect we'll see Springer act as our primary DH over the next couple of weeks - but once he's able to return to CF full time, Tellez will be recalled to split time at DH. That timeline probably aligns well with the continue decline of Grichuk back to the 100-110 wRC+ hitter he is and he'll return to a platoon role with Tellez and/or can spell Gurriell in LF, who's been equally as bad offensively and defensively so far this year.