Anyone that says they'd be worried about either of those guys has set their definitions of what is a starter and what is a reliever too strictly.
Sure you can set your team up with "Starters" (25+ durability/75+ Stamina) and "Relievers" (60+ DUR/25 STA) but to say that these guys worry you or can only pitch 60-70 innings means that you clearly don't understand how to use a player like this.
That said, the first guy will be able to pitch more innings, but the 2nd guy will be a better pitcher. Thus it comes down to whether you'd rather have ~140-150 innings of good or ~100-110 innings of better.