Issue: As a 24 year old Jair Jurrjens followed up a fine 2009 season with a shortened 2010 season because of injuries. He seems to be fine in Spring Training, so who will he become over the rest of his career and most importantly in 2011? Will he pitch like Hall Of Famer Juan Marichal or Scott Sanderson?
Facts: Bill James created formulas in order to compare players of different eras. Comparing Jair’s career to date to other pitchers’ careers at the same age there are at least 10 similar hurlers. We’ll use 2 of them to compare careers in order to peer into the future of J.J. The two pitchers are Hall Of Famer Juan Marichal (16 season career) and Scott Sanderson (19 season career).
First, actual career stats for all 3 through age 24, then Marichal’s and Sanderson’s career stats beginning with the season they turned 25 and going through the remainder of their careers:
(ERA+ is adjusted to the hurler’s ball park. Counter intuitively the higher the better, with 100 = the league average.)
| Player | From/To | Yrs | W | L | ERA | GS | SHO | IP | H | ER | HR | BB | SO | ERA+ |
| Jurrjens | 2007-2010 | 4 | 37 | 27 | 3.52 | 92 | 0 | 550.3 | 518 | 215 | 43 | 198 | 390 | 117 |
| Marichal | 1960-1962 | 3 | 37 | 23 | 3.44 | 74 | 7 | 529 | 475 | 202 | 63 | 166 | 335 | 109 |
| Sanderson | 1978-1981 | 4 | 38 | 28 | 3.10 | 88 | 8 | 577.7 | 528 | 199 | 47 | 162 | 390 | 115 |
| Player | From/To | Yrs | W | L | ERA | GS | SHO | IP | H | ER | HR | BB | SO | ERA+ |
| Marichal | 1963-1975 | 13 | 206 | 119 | 2.79 | 383 | 45 | 2978 | 2678 | 924 | 257 | 543 | 1968 | 125 |
| Sanderson | 1982-1996 | 15 | 125 | 115 | 4.06 | 319 | 6 | 1984 | 2062 | 894 | 250 | 463 | 1221 | 98 |
Next, Marichal’s and Sanderson’s age 25 season actual stats, because in 2011 J.J. will be the same age:
Marichal
| Year | Age | Tm | W | L | ERA | GS | SHO | IP | H | HR | BB | SO | ERA+ | WHIP | H/9 | SO/9 | SO/BB |
| 1963 | 25 | SFG | 25 | 8 | 2.41 | 40 | 5 | 321.1 | 259 | 27 | 61 | 248 | 133 | 0.996 | 7.3 | 6.9 | 4.07 |
Sanderson
| Year | Age | Tm | W | L | ERA | GS | SHO | IP | H | HR | BB | SO | ERA+ | WHIP | H/9 | SO/9 | SO/BB |
| 1982 | 25 | MON | 12 | 12 | 3.46 | 32 | 0 | 224 | 212 | 24 | 58 | 158 | 106 | 1.205 | 8.5 | 6.3 | 2.72 |
Analysis: The comparisons are fascinating. Through age 24 J.J. has the best ERA+, yet Scott is better in that same category than Juan. Likewise, J.J. has given up the least HR and is tied for most Ks. At this point J.J. could be either one and Sanderson was a better pitcher than Marichal early on. When we look at the rest of the other 2 hurlers’ careers some things stand out. Juan was clearly the best. ERA, ERA+, IP, Ks, and Wins are where he easily separates himself from Scott and hammers down Hall Of Fame type production. And how about Juan’s 45 shutouts over the remainder of his career? Not bad. Lastly, the 25 year old seasons also tell us something. Scott is a .500 pitcher, while Juan earns as many wins as his number of birthdays. We think J.J. is a season behind these 2 due to injuries and surgery last season, so we feel his break-out season will be in 2012, not 2011, but he will still be a fine starting pitcher this season. J.J. in 2012 could be either of the other 2, but this season shall give us a nod in which direction- HOF candidate or a little better than a .500 hurler.
2011 Projection:
| Name | Team | $ | W$ | S$ | ERA$ | WHIP$ | K$ | Pos$ | W | S | ERA | WHIP | K | IP | |
| Jair Jurrjens | ATL | SP | 8 | 2 | -1 | 1 | 0 | 1 | 5 | 11 | 0 | 3.47 | 1.27 | 129 | 166 |
{6-4-3 Assists to Last Player Picked and Baseball-Reference.}