Early on I'd say even WL is fine, but when the playoffs roll around, I'd say neither WL or Pro would work because I'd be VERY concerned at his fumble chances. Your elusive back could doom your team in the playoffs. The OC would have to run you outside to avoid the hard hitting D-Linemen. If he runs you inside, that's a fumble waiting to happen. The issue is you may not have the speed to run outside, so it's a lose-lose situation for the offense. This is why I feel elusive backs have the worse life expectancy in GLB (just like in real-life I suppose).
I'd play it safe and do AAA. Unfortunately, Mentor is being removed next season, but if you're desperate to play WL/Pro, you could consent to being Special Teams cannon fodder =).