Luis Castillo, as some of you know, owns most of the Florida Marlins career batting records, including games played, hits, stolen bases, and a number of other categories.  He has had, arguably, the greatest career as a Marlin of any who have played here.  As such, his status as a free agent after the 2006 season ends will be of particular interest to fans and team management.

The question, of course, is how long can we expect Castillo to play and can he perform well enough for the Marlins (or whomever chooses to pay for his services) to justify a three-year contract beginning in 2007.

To do this, I looked up all the second basemen who had played at least 900 games at second base, and had their debut after Opening Day, 1970.  Forty seven players make the list, starting with Robbie Alomar (2320 games) and ending with Marty Barrett (908).  Then, I determined their age on the date of their debut (rounding to the nearest year) and ran basic Runs Created data for each season that the player was active.

When you look at the Runs Created data, you see an obvious pattern.  Once a player stops contributing at least 60 runs in offense, the player’s career comes to a halt.  In a couple of cases, a team would carry someone who contributed, say, 45 – 55 runs each season if the player was considered a solid glove man.  Manny Trillo and Doug Flynn were the two most obvious players where a glove carried the bat, though Rennie Stennett was given a couple of extra years at the end of his career by the Giants even though he was no longer putting any runs on the board.  Still, once the player drops below 60, the player is usually given one good shot at returning to form – and if it fails, his days as a regular ends.

Knowing that 60 runs was the end of the line for a second baseman, the next step was to determine the age at which the players fell below the line, and see if there was a common ending point based on the age of the player.  Luis Castillo debuted about one month shy of his twenty-first birthday, so I was especially interested in the data for players who got their start at 21.  Making that list were Willie Randolph (2152 games), Bobby Grich (1765), Delino DeShields (1392), Glenn Hubbard (1332), and Carlos Baerga (1063).  Castillo has now played 1114 games at second base having passed his 30^th birthday last September.

First, let’s look at the age when each player fell below replacement level hitting.  Willie Randolph was 34 when he had his first really off season though he was able to put it back together and contribute for a few more seasons, Bobby Grich was 35.  Delino DeShields lost it very suddenly at 32, while Glenn Hubbard was 31 when the glove no longer could carry his bat.  As for Carlos Baerga – he’s the odd man out having fallen from a great player to a replacement level player at 27.

The average number of games played by this group (not counting Castillo) is 1541.  So, if Castillo’s legs could stay healthy it is not unreasonable that he could play three more decent seasons – and even sneak in a fourth.  (Over his seven full seasons, Castillo has played an average of 137 games.)  From a batting standpoint, however, Castillo is approaching the 60 run barrier.  Without making modifications for the ballpark – one assumes that the slap-hitting Castillo is little affected by the distance to the outfield walls – Castillo has declined in productivity for two consecutive seasons.  In the last four seasons, his runs created data reads 90, 95, 78, and 66.  He still has an above average glove and is fantastic at turning double plays, so if Castillo was to slip to the 50 run range, he might be kept for one last go.  However, leg injuries will affect mobility – and that affects range.

In order to get a two or three year contract in 2007, Castillo will have to rebound with a healthier season than the one he had in 2005.  Likely, he will have to play closer to 140 games and help put 80 runs or more on the scoreboard.  If so, Castillo will command a decent salary on the open market – and may be priced outside what the Marlins would be willing to pay.  Anything less, however, and Castillo may find the market a bit smaller than he had hoped.  Either way, the Marlins will need to start looking for options in case Luis is either on the disabled list or the list of eligible free agents.

(NOTE:  This was written before Castillo was traded to the Twins.  If you would like to see the article including tables of data related to this article, send me contact info.)