Second Half Stars and Slumpers
So you're behind in the standings and wondering why the guys you thought would carry you aren't cutting it.  Well, before you trade for Kent Bottenfield or Matt Williams, you'd better know what you're getting and what you're giving up.  So today I'll look at a some guys who have had great years so far, but show a history of tailing off after the break, while looking at some others who have had OK years but are monsters in late summer.
The Diamondbacks have a couple of guys in both camps.  Both Matt Williams and Luis Gonzales have been awesome so far this year.  Unfortunately, if history is a guide, their awesomeness will be limited to the first half.  Williams shows a marked decrease in power in the second half, losing 40+ points in slugging over the past 3 years.  Gonzales actually increases in power in the second half, but loses almost 40 points in batting average.  On the flip side, Jay Bell and Bernard Gilkey actually get better as the season wears on.  Bell's numbers increase around 30 points across the board.  But Gilkey positively explodes after the break.  His batting average increases by nearly 50 points and his slugging goes up over 80 points.  Look for Gilkey to see much more playing time in the outfield as the D-backs experiment with Womack back in the infield.
Barry Larkin has had an ordinary year in 1999, at least by his standards.  Of course, the same could be said of Larkin every year at this time.  He has averaged in the first half a .292 batting average and a .469 slugging.  This year, he's at .301/.456.  But in the second half, Larkin becomes quite a different animal.  Over the past several years, he's averaged .325/.600 in the second half!!  Another Red with distinct production in both halves is Greg Vaughn, although in the opposite direction.  Over the past three years, Vaughn has been quite good in the first half, averaging .275/.561 before the break.  The story is not so good in the second half - .226/.479.  However, some of the decline might be attributable to his mid season trade from the AL to the NL in 1996 (remember when Milwaukee was an AL team?).  He was platooned in the second half of 1996 and most of 1997 and didn't take to well to the arrangement.  However, even last year when he was happy with his playing time, his numbers decreased in the second half to .242/.520.  Another concern is that if the Reds' starting pitching can't keep them in the playoff race, he might be dealt to the power hungry Red Sox.  Something to keep an eye on.
Vinny Castilla has had a pretty disappointing first half, but don't despair - he has a history of upping the ante in the second half, boosting his numbers across the board by nearly 40 points.
Carl Everett has had a career year so far, but his recent hamstring pull will certainly slow his stolen base production.  If Hidalgo catches fire over the next month, Everett might also be looking at reduced playing time when Alou returns.  Also working against Everett is his history of declining production in the second half, dropping in batting, on base and slugging by 23, 20 and 53 points respectively over the past 5 years.
Russ Ortiz might not have trouble this year but he will have trouble.  Dusty Baker has consistently let him rack up high pitch counts this season, reaching 127 pitches 7 times in 19 starts, once allowing him to throw 140 pitches.  For a young guy who became a starter only last year, that's a lot of stress.  By comparison, Curt Schilling has reached 127 pitches only 3 times this season.
Many analysts think Henry Rodriguez has a history of fading in the second half.  While it's true that his numbers over the past several years do drop a tad in the second half (down 40 in slugging, -20 in batting average), last year he actually improved in all categories significantly (up 30 in batting, +50 in slugging), so he might be reversing a career trend.  His problem is that he has a tendency for lousy Septembers.  So don't sell him just yet.  Surprisingly, Sammy Sosa actually drops off in the second half, although only very slightly - less than 10 points in average and slugging.  Every once in a while, you'll find a player that strains the credibility of this exercise.  Glenallen Hill is just such a player.  He has had a monster year so far and his career trend indicates he's gonna get even better, with second half improvements of nearly 40 points in batting average and 20 points in slugging.  A more likely scenario is that he comes down closer to his overall career numbers, closer to .280/.500 than to the .350/.700 he's at now.  Benito Santiago for some unexplained reason, goes against the trend for catchers wearing down in the second half.  In each of his last 2 full years behind the plate (96 & 97) Santiago hit below .245 in the first half.  And in each of those years he hit above .280 in the second half with increased power.  With most of the Cubs games at home the rest of the way and Jeff Reed to occasionally spell him, look for that trend to continue.
Two youngsters that look ready to surge are Ruben Rivera and JD Drew.  Rivera looks like he has turned his season (and his career) around, hitting .326 and slugging .698 in July.  Padre hitting coach Merv Rettenmund has quieted his stance and Rivera now looks very calm and comfortable at the plate.  While he still strikes out a lot, his walk rate is up dramatically.  Of his last 15 hits, 9 have been for extra bases, 5 of them homers.  Drew is the most talented rookie in the NL until Ankiel gets the call.  He re-discovered his stroke in his rehab stint in Memphis and I  wouldn't be surprised to see him finish July with a .280 average and the season with 20+ homers, 60+ RBI and a .300+ average.
Last year through the first 4 months, Andy Ashby was arguably the best pitcher in the NL.  Then he pulled a butt muscle, which threw off his mechanics and he struggled through the last two months and the playoffs.  After struggling through parts of the first 2 months, he's been brilliant, and now leads the league in shutouts - one of which came at Coors.  If he can remain healthy, and with the Padre's continued improvement, he has an outside chance to win 20.
Lastly, Ed Sprague has had a career year so far.  And that's about where it's gonna stop.  His average goes gown 30 points after the break and his slugging drops by nearly 90 points.  Ouch!  Look for the drop-off over the next few weeks, as the Pirates take on the Mets, Braves, D-backs and Reds in 20 of their next 32 games.
Although it's quite possible that any of these players could continue to play as well or as poorly as they have so far, their career trend weighs against it.  Barring injuries, at least you'll know what to expect.  Obviously, there are plenty of players I didn't cover.  I'll be happy to address any players you suggest.  Just email me at the address below and I'll post his numbers in the next available column.