Not so very well, though.

I--I don't seem to please Marvin very well with tackling." "Oh, you'll get onto that all right," said Andy cheerfully.

"Fact is, I don't think a fellow ever really learns much at the dummy.

It's dumping a chap in real playing that shows you what's wanted.

Don't you think so, Hat ?" "Dummy practice is a good thing," answered Williams morosely.
He sat tilted back on the chair, hands in pockets, staring at the floor.
He seemed a gloomy sort of fellow, Steve thought, and was relieved when Williams added: "Guess I'll run over to Johnny's for a minute," and, muttering something about being glad to have met the visitor, found a cap and wandered out.
"I suppose," said Steve, when the door had closed, "it's necessary for a fellow to learn how to tackle, but it seems to me that if you aren't awfully good at it you might get a chance to show what you can do besides that." "I guess I don't quite understand what you mean," responded Andy.
"I mean that if I can't tackle the dummy well enough to please Marvin," answered Steve a trifle bitterly, "I do as well as lots of other fellows, and--and it doesn't seem fair to keep me back just for that.
Lots of fellows have been taken on to the second squad that can't play as well as I can, Miller." "Oh! I see." Andy's eyes narrowed a little and he looked at Steve more intently.