Evaluating the relative merits of players is a subjective business,
but not entirely. When I was attending jai alai regularly and
betting considerably, it was vital to be able to properly evaluate
players. While it is always necessary to make adjustments for
injuries, and for players improving or going downhill, there are
objective ways to go about ranking players.
First (obviously) you have to look at whether they are early, middle, or late game players. When someone new is added, if you know where they were playing before and against whom, then you have a better chance of slotting them in properly at your fronton.
Second, keep track of whether they are playing regularly in the high or low post positions. This will tell you how the player manager handicaps them. It does not take long before you can develop a ranking of the entire roster according to the player manager's evaluation. By the way, although the 7 is mathematically the toughest post, all the players and the player manager at Bpt swore that the 5 was the 'honor position' and handicapped accordingly.
But that reflects the 'official' rankings of the player manager. You need to develop your own evaluations. This I did by keeping a set of statistics for every player. It was similar to the ratio of winners to unforced errors in tennis. During the games, I would note in my program a + every time a player made a difficult catch or scored a putaway shot (not just a thrw that someone dropped). I'd note a minus (-) for every dropped ball, ball thrown out, or missed opportunity to put someone away. These were occasionally a little subjective, but definitely unbiased, since I was using this for betting purposes.
Over the years, I posted these at the end of each season on index cards I maintained for each player, so that I have lifetime ratios of plusses to minues involving hundreds (and even thousands) of observations.
As a result of all the discussion on this board, I dug out my old cards. In the front court, here are the cumulative ratios (1976-88)for the various 'greats' we have been discussing, as well as for a few others. One of the interesting things is that you don't find early players with high ratios even though they are playing easier competition. Similarly, the fact that they are playing other greats does not seem to lower the ratings of late game players.
Guernica II 1.9 (also played as Beascoechea)
Michelena 1.8 ( limited observations early in his career)
Asis 1.7 (skewed heavily due to singles)
Obviously I can't list everyone here.
In the backcourt, the plus/minus ratios are not as true a measure since there are fewer opportunities for putaways in the backcourt, and there are a lot of guys who just catch and return but not much else. I never could find a way to give someone like Goyo or Javier or Boniguen plusses for putting pressure on their opponents, which they often did, although without necessarily scoring.
Nevertheless, Churruca had a 1.6, which was the best of backcourters, even though he was at the end of his career.
For backcourters, the plusses and minuses were helpful over short periods, but the lifetime figures are not as useful.
Anyway, from the front court ratios you can see how I tended to place some guys higher and lower. Remember, these numbers involve a very large number of games.