For what it's worth, judging by their cards, Barker at F0 is likely to be a much more effective pitcher than Leal at F9.
If it was my personal choice, I'd rather see Barker pitching in that situation, based on Barker's pretty good card and Leal's absolutely terrible card. HAL might have felt the same way about the choice between those to pitchers under an emergency situation. If so, HAL's decision to call on Barker might be considered a feature rather than a bug.
Update: Also, has just been noted in an edited reply above, since Leal is not rated as an RP, he would likely come in as an F0 as well. In this case, Barker was definitely the better choice.