ERC# means nothing. Throw it out and ignore it. The SIM does not use ERC to calculate the result of any batter/pitcher match-up. Nor does it use ERA+. Only raw ERA is used in any form, and even then just as an estimator of 2B and 3B rates allowed.
By far the most important numbers for pitchers are OAV, HR/9 and BB/9, but arguably the most important step of the PA outcome decision tree is whether the AB results in a hit or an out, and the only statistical inputs that come directly from the batter and pitcher in that calculation are AVG and OAV. The result is determined using batter's AVG, pitcher's OAV, their respective league averages, and some assigned matchup weights for each stat. The calculation is here:
H/AB = ((1.066*AVG * .934*OAV) / LgAVG) /
((1.066*AVG * .934*OAV) / LgAVG + (1.066- 1.066*AVG )*(.934- .934*OAV)/(1-LgAvg))
Where, LgAVG = (.934*PLgAVG + 1.066*BLgAVG)/2
There are other influences on this outcome like platoon (handedness) adjustments and park effects, and understanding the matchup weights can help guide some decisions as well, but you can go further down the rabbit hole as you play longer and read more. If you want to experience some degree of success early on to keep up interest and morale, focus your pitcher drafting decisions on the best combos of OAV, HR/9 and BB/9 relative to $/IP. Find the values and play ball.