There are two important reasons not to put too much stock into AFL performance. The first reason is that players accumulate far less playing time in the AFL than they do during the minor league season. The second is the league’s wild offensive environment.

Tampa Bay’s Rhyne Hughes, for example, had a very good performance in the AFL and hit .394/.432/.697, but it was in 118 plate appearances. During the regular season with Double-A Montgomery, Hughes had 450 plate appearances, nearly four times as many PAs as he had in the AFL. So to keep Hughes’ outstanding AFL performance record in perspective, we need to give his 2008 minor league performance record a 4:1 weight. There’s nothing wrong with paying attention to AFL performance; the problem is when people treat the AFL as a separate season and give it equal weight to a full minor league season.

Another important consideration is that the offensive environment in the AFL is extremely high. This year, the league averaged 6.9 runs per nine innings (per team); the league average in MLB this year was 4.7 runs per nine innings, and even the hitter-friendly California League was “only” 5.2 runs per nine. We can account for that, but it’s important to remember how much the AFL inflates offense when you look at the raw numbers and see a hitter is batting .300/.365/.475; after all, that’s just about the league average.

This is of course to say nothing of the importance of first-hand visual observation and scouting reports, just a reminder that any “AFL breakout” performance is almost always more illusion than reality.

I’ve read that the AFL is where organizations send many of their best prospects, but then I’ve also read Baseball America writers posit that one shouldn’t read too much into the results from the AFL.

If a prospect puts in a good showing against such top competition, why would it be unwise to put much stock in his results?