I'm sorry to say it, but Small will never even come close to being a big league SS. He's already in his third full pro season, and his fielding numbers have barely improved over the course of the year. For a ML SS, ideally you want all 4 of those fielding attributes to be at least 80 for him to be useful, and he's not 80 in any of them. He may surpass 80 in arm strength, but overall I would never stick him at SS or CF. 2B is a maybe if his range develops a bit more, but I think he's most useful at 3B, where he will be Gold Glove caliber with his above-average range and arm.
Johnson is obviously not going to win any batting titles but my philosophy is that hitting should be considered gravy at SS and fielding is most important. Unfortunately he's not quite a true stud at SS, but his range, glove, and arm accuracy make him a solid defender and his elite arm strength probably pushes him into territory where he would be in the upper echelon of fielding SS's in an average league. I would try to look for another option to give you a better combo of hitting and fielding, but at the moment I'd probably stick with Johnson as he's the only guy who won't actively hurt you at SS.
One glaring thing I see with your team is that you're apparantly starting
Lyle Walters at 2B, which is an enormous mistake. He doesn't reach ANY fielding recs for a 2B, and 2B is the second most important position on the field. It might be hard to stomach, but Walters is a LF at best and has no business playing any infield position other than 1B. If you want to boost your winning percentage, moving him to another position and replacing him at 2B is a good way to start. Here's what I would do: banish Walters to LF or 1B (or trade/bench him if you don't want to replace your current guys at those positions). Leave Johnson at SS and move McCallum to 2B. Then bring up Small and slot him in at 3B. All of a sudden you've got a very good infield on your hands.