No doubt he had something probably pine tar on his hand. It helped him get a better grip, which helped him be more effective. Probably not the same effect as a spit ball, but it did help him. I think it is the same as grabbing the rosen bag, which is confusing as to why that is allowed, but Pine tar isn't. Same thing, just a different substance.
At the same time, and I think the reason LaRussa didn't make an issue is it opens the door in National league parks to the same thing to his pitchers. Pitchers hit in St. Louis, and they will use pine tar on the bat, which will transfer to their hands. Happens every day in the NL, and no one says anything.