As you may know, I enjoy trying to predict the future for ballplayers . So, when A-Rod got his 3000 th hit, a thought crossed my mind: could I apply my framework for predicting future Hall of Famers to milestones like 3000 hits? This is the result.
What I did was as follows: first, I went through the 29 players with 3000 hits and checked where they all stood hit-wise at each age. Then, I looked at the median mark for the group, and checked how many ballplayers in history had reached that number of hits by the same age. Then, I took a straight percentage of how many of the total number of players at that mark actually wound up over 3000 hits.
For an example, say that the 15 th most hits at age 20 among 3000-hit players was 100. I then looked at how many players in history had 100 hits through their age 20 season, and figured out the percentage of that number that went on to 3000 hits. After that, just to get another benchmark, I repeated the process with the lowest hit total in the 3000 hit club by age (and second lowest, since many of the lowest marks were by Cap Anson , who played in such a radically different time that I wasn't sure how useful of a marker he'd be for other players).
With the percentage of players at each milestone that went on to 3000 hits, I then looked towards the game today, checking the leaders of each age bracket today against the historical marks.
23: Median-467 Hits (14.02% at this point make it to 3000)
Second Lowest- 80 Hits
I'm going to include everyone younger than 23 here, since there are so many good young stars in the game today. We only have one 23-year-old at this mark. Mike Trout , with 656 hits (all stats are as of the morning of 6/28) has already reached the median for next season, and should easily be halfway to the age 25 mark by the season's end. I don't have the specific numbers, but I figure being this far ahead of the curve has to give him a significant leg up on his chances of reaching 3000.  
However, in addition to Trout, we have 22-year-olds Bryce Harper and Manny Machado . Neither has 467 hits yet, but both are over 400 (436 and 416, respectively), meaning that they should easily cruise by this mark an entire season early as well. No other 23-year-olds will reach this mark in 2015, but check back next season to see how Xander Bogaerts (22, 216 hits) is doing. 23-year-old runners-up include Christian Yelich (285) and Nick Castellanos (200), so they're technically still ahead of where Wade Boggs (who debuted relatively late) was as this point (which really says more about how impressive Wade Boggs was than their chances, to be honest).
24: Median-584 (11.19%)
No players above the median here, although leaders Nolan Arenado (334), Yasiel Puig (320), and Marcell Ozuna are ahead of where some 3000 hit club members were at the same point (namely, Boggs, Lou Brock , Honus Wagner, and Craig Biggio ).
First among this age group is Starlin Castro , with 923 hits so far. Assuming he's healthy, he might hit next year's 995 mark by the end of the season, although his drop off and the crop of rising Cubs stars might cut into his playing time. No one else is at 807 hits yet, but Freddie Freeman had a pretty good chance (732) before his DL-stint. Assuming he's not making it, our next best chances would be Jason Heyward (714) and Jose Altuve (711), although even if they make it, there's still not even a 1-in-5 chance at this stage. Next on the list is Giancarlo Stanton , but his injury and distance (693) makes it unlikely.
26: Median-995 (20.27%)
Elvis Andrus leads the way, with 1027 hits (nearly double second place Mike Moustakas 's total of 516). But given his regression on offense the last few years, I'm not sure how many more seasons we can expect to see him above the 3000-hit median.
27: Median-1175 (23.08%)
Justin Upton might make it to 1175 by year's end (he's at 1116), but outside of him, no active 27-year-olds are even to 650 hits.
28: Median-1327 (21.13%)
For the second time, we have no players above the cut-off. Andrew McCutchen leads 28-year-olds with 1063 hits and counting, which tops about a sixth of the 3000 hit club, but he's still