Every year after the end of the regular season, each major league franchise selects several of its minor leaguers to play winter ball in the Arizona Fall League. The league is run by MLB and is filled predominantly with players from the upper levels of the minor leagues, in a lot of ways making it a finishing school for prospects that are close to the big leagues. The AFL tends to be hitter friendly, with the ball jumping off the bats in the Arizona desert heat. The season runs for a little over a month, so the results and statistics compiled are just a small sample compared to an entire minor league season. However, it’s still worthwhile to take a look at how the Mets prospects fared in the fall league, and why the Mets chose those players as participants.Let’s start out by looking at the four pitchers the Mets sent to the AFL:Brad Holt was the most prominent Mets prospect sent to the AFL this year. Holt has been one of the Mets top pitching prospects since he was drafted 33rd overall in 2008. Holt was sent to Arizona because he had a disastrous year in 2010, to say the least, and the Mets wanted to try and get him back on track, as well as get him some confidence heading into next year. Holt had an ERA of over 10 in 30 innings for AA Binghamton before being demoted to the Florida State League where he went 2-9 with a 7.48 ERA against a league he dominated the previous year. Worse than those stats is the amount of walks he surrendered and the decrease in velocity on his fastball, which had previously been his best asset and the primary reason for his high prospect status. In his first three starts in the AFL, Holt pitched a total of nine innings, giving up no earned runs, while striking out nine, walking four, and giving up just four hits. Those numbers show an improvement in his command; however, his fastball was reportedly 90-92 for the most part, which is an improvement but still slower than what he showed in years past. Holt then struggled in his final start and made another appearance out of the bullpen where he did not fare well either, but the first three starts were enough to earn him pitcher of the week honors on October 25 and garner a selection to the AFL Rising Stars game. Most importantly, three out of four good starts in Arizona gives a glimmer of hope that Holt can recover from a horrific 2010 and rebound in 2011.Perhaps the second most prominent pitching prospect the Mets sent to Arizona was lefty Robert Carson. Starting the season in the Florida State League, Carson fared well, but wasn’t spectacular before being promoted to AA where he struggled, earning just one win in ten appearances and posting an ERA of 8.32. This prompted the Mets to send him to Arizona to face competition that is close to the AA level, hoping he will be prepared to handle that level to begin 2011. Carson made six starts in Arizona, pitching well in three of them while struggling in the other three, but was never able to put together back-to-back quality starts. As impressive as Carson was in three of his starts, it does not outweigh his final stats for the fall season: 16 runs on 27 hits in just 18.2 innings, with 14 strikeouts and just five walks. The lack of walks is good to see, but perhaps too good as the 27 hits indicate he was always in the strike zone instead of trying to extend the strike zone and make hitters swing at bad pitches. Judging off the goal of being prepared for AA to begin 2011, it’s difficult to conclude that Carson will in fact be better prepared to face AA competition after his participation in the AFL. With only one year left before he is Rule 5 Draft eligible, if Carson does not start to show more consistency at the start of 2011, the Mets may have to consider transitioning him into a LOOGY if he’s going to reach the majors.The third Mets pitcher in the AFL was righty Nick Carr. Carr is a hard thrower with a plus fastball who the Mets sent to the AFL because he hasn’t been able to pitch a lot the past two seasons because of Tommy John surgery. Carr had his breakout season in 2007 for Brooklyn when he was a starter, but made the transition to reliever in 2009 prior to having his TJ surgery. In 10 relief appearances in Arizona, Carr threw 16 innings, but put up an ERA over 5 and walked more batters than he struck out. Even though Carr is still making his way back after surgery and has a plus pitch, the Mets did not protect him from Rule 5. However, there’s a good chance he isn’t selected, so the Mets will be able to keep him in the farm system and will look for him to hone his command and develop into a useful bullpen piece.The final Mets pitcher sent to the fall league was lefty Eric Niesen. As a lefty with good velocity, Niesen had a great 2009 as a starter, having a great strikeout to walk ratio and making the Florida State League All-Star team. However, in 2010 his walk and strikeout numbers went in the opposite direction, which prompted a move to the bullpen. With Niesen Rule 5 eligible this year the Mets sent him to Arizona for one final look before making a decision on him. But after putting up a 5.40 ERA with a WHIP of nearly two, the Mets passed on protecting Niesen, who could still end up being in a major league bullpen as a LOOGY, but he would have to regain his 2009 form.Now let’s take a look at the position players the Mets sent to the Arizona Fall League:The most familiar name of the position players the Mets sent to Arizona was outfielder Kirk Nieuwenhuis, who didn’t find a job in the Caribbean over the winter, so the team used their outfielder spot in Arizona on him. Nieuwenhuis had been swinging a hot bat since mid 2009, but it finally tempered when he reached AAA for the final 30 games this past year. In the short AFL season, he had only 90 at bats, in that time he had eight extra-base hits and struck out 25 times. Those numbers show little or no improvement over his month in AAA, meaning Nieuwenhuis did not progress all too much as a result of playing in Arizona. The AFL is also too brief a season to shed much light on if Nieuwnhuis is capable of being an every-day centerfielder. If Mets fans were expecting him to be on the opening day roster in 2011, his play in the AFL only reinforces the notion that he will start the year in AAA, still with plenty to prove at that level.Jordany Valdespin is another name Mets fans might know that they sent to the Arizona Fall League. The second baseman was sent to Arizona to have one final audition for the 40-man roster, which he passed, as the Mets have added him to their 40-man roster to protect him from the Rule 5 Draft. Before having to leave the league early due to an injury, Valdespin hit .355 with 5 extra-base hits and 11 RBI’s in just 19 games. Most importantly he drew four walks in just 76 at bats, a definite step in the right direction after walking 10 times in 382 at bats during the regular season. It’s just a small sample, but his numbers in Arizona show recognition of his shortcomings and some progress as he works on them. Now saved from the Rule 5 Draft, Valdespin needs to continue his improved patience at the plate and depending on how things play out, he could be in a position to get to the big leagues by the latter stages of 2011.Another second-base prospect the Mets sent to the AFL was Josh Satin. The numbers on Satin are an even smaller sample than everybody else because he was on the taxi-squad for much of the fall season, meaning he was only eligible to play twice a week. In only 41 at bats across 12 games Satin did hit .390. Satin has hit at every level he has been at, playing in his league’s all-star game the past two years, so hitting for that average in a short time isn’t surprising. The issues that Satin has are that he’s starting to get old and he isn’t great defensively, which means he’s a long shot to garner any serious attention in spring training to be the Mets second baseman, even though that position appears to be an open competition at the moment. He is currently trying to increase his versatility defensively so he one day might have a chance to be a major league utility player, which is a possibility for him despite his age because he can hit, but at the moment he has little experience outside of second base.The final player the Mets had in the Arizona Fall League was Kai Gronauer, a native of Germany. Gronauer is a catcher who is solid enough defensively to possibly have a future as a backup in the majors. He had a great debut with the bat in the Gulf Coast League in 2008, followed up by a mediocre 2009 in the South Atlantic League. He returned to the SAL in 2010 and hit well enough to get a mid-season promotion to St. Lucie where he hit .324 with seven extra-base hits across 38 games. The Mets sent him to the AFL to give him his first experience against upper-level pitching. In Arizona, Gronauer hit just .222 in 45 at bats, struggling early on, but collecting eight hits in his final six games. Of course it’s a small sample, but there is some hope that a year from now Gronauer could be the third or fourth option at catcher in the organization, which doesn’t sound like much, but the Mets should know better than anyone the need to have minor league depth in case of injuries.