Entering this season many Giants fans looked at Tim Lincecum and Matt Cain as Twin Towers of Twirling.  They figured both were potential aces, All-Stars and even Hall of Famers.

Suddenly Lincecum has emerged as the potential hardware bearer, while Cain has struggled to get the lead out.  Matt uncharacteristically gave up nine earned runs in one start.  Tim has given up nine earned runs total in eight starts.

Why the sudden split in direction by the two 23-year-olds?

With the help of the PITCH/fx data so graciously provided us by Josh Kalk and by analytically looking at both pitchers' splits, we can examine the reasons, perhaps identifying how both pitchers can continue to improve.  Here are some of the reasons for the difference:

1.  Tim has been phenomenal with runners in scoring position.  With RISP he has limited the Giants' opponents to a .115 batting average, a .222 on-base percentage,  and a .173 slugging percentage for a nearly invisible .395 on-base-plus-slugging percentage.  Matt has struggled once runners get into scoring position, allowing a poor (and uncharacteristic) .314/.372/.514/.886 in comparison.

Lincecum showed at Fresno a year ago how tough he could be with runners on base and in scoring position, allowing just one hit with runners on and nary a hit with RISP in his five starts there.  But NO ONE is as good in this regard as Tim has been.  Tim has shown a true propensity for being able to really buckle down when he most needs to, but it seems highly unlikely he can continue to hold teams below a .400 OPS with RISP.

On the other hand, unless he has suddenly lost the ability to pitch out of the stretch, Matt is almost sure to improve his performance with runners in scoring position.

2.  Both pitchers pitch much better when they throw first-pitch strikes.  But while Matt's difference is pronounced, Tim's is huge. 

This season Matt has limited batters to just a .218 batting average, a .256 on-base percentage and a .336 slugging percentage when he gets his first pitch over.  That's an impressive .592 OPS against.  When his first pitch is a ball, he is quite hitable, allowing batters to rake him at a .286/.435/.476/.911 pace.

Tim's difference between a first-pitch strike and a first-pitch ball is even greater.  When he has gotten his first pitch over, Tim has limited opponents to a paltry .219/.240/.263/.503 line.  When he gets that first pitch over, he becomes Greg Maddux-stingy with his walks and makes every hitter look like Manny Burriss when it comes to yielding extra-base hits.  If his first pitch misses, he falls back to a level very close to Matt's, at .282/.402/.493/.895, in which batters look almost like the latter-day saint, Barry Bonds.

Not only is Tim even tougher than Matt if he gets that first pitch over, he does so considerably more often.  Matt has really struggled with his first pitch, finding strike territory just 53.0% of the time.  Tim's 61.6% first-pitch strikes is up from 55% last season and may be the biggest single sustainable factor in his rapid rise this year.

3.  Matt has lost one mph off his fastball this season, while Tim's has picked up by half a mile per hour.  Since Tim's average fastball is 2.5 mph faster at 95.5 than Matt's 93.0, it is even harder to catch up to. Even more importantly, this leaves Tim's fastball 12.1 mph faster than his change up, while Matt's heater is only 6.4 mph above the speed of his change.

Matt's fastball, curve and slider move very similarly to Tim's, and his change up actually moves 2.6 inches MORE sideways and drops by 1.2 inches more than Tim's.  But Tim's greater speed differential between his fastball and his off-speed pitches makes them tougher to hit than Matt's.

4.  Most pitchers' hardest pitches to hit are their off-speed deliveries.  Still, they throw predominantly fastballs because they can control them better, because they have more confidence in them and because they are macho.  Part of the reason Tim has outpitched Matt is because Tim throws his off-speed stuff about a third of the time compared to Matt's only about a fourth of the time.

We saw that Tim's fastball velocity has improved this season and that Matt's has declined slightly speed-wise, yet Tim throws his most effective pitches far more frequently than Matt.  In particular, he uses his change up 21.0% of the time compared to Matt's 14.4%.  The change up has been each pitcher's toughest pitch to hit, but perhaps for control reasons Tim has used his more often.  Add in that Tim has nearly twice as much velocity difference between his fastball and change as Matt has, and clearly Tim is getting more juice from the change up than is Matt.

The result is that Tim has been much harder to hit for power than has Matt, now having yielded only three homers to Matt's six.  (Matt's six homers include the one he gave up last night.  All other stats used here preclude Matt's last start.)

5.  Matt has really struggled with his control this year. Last season he was at 63% strikes, and Tim was at 62%.  This year Matt has thrown only 60.7% strikes, finally reaching the 60% mark for the season in his start on May 8th.  Conversely, Tim has improved his control, throwing strikes 64.5% of the time.

Tim's walks are at only 3.22 walks per nine innings, after he walked 4.00 per nine in his rookie season.  Matt's walks have ballooned to 4.89 this season, up from a career best 3.56.  Tim's walks have been consistently dropping since his sophomore season of college.  Matt showed great control promise by walking just 1.80 batters per nine innings the last two months of the 2007 season.

But it is Tim who has continued to improve his control this season, while Matt has struggled.

So in summary, Tim has been especially tough with RISP while Matt has struggled, Tim has gotten his first pitch over far more consistently than Matt, Tim's fastball has improved while Matt's has slowed to the detriment of both Matt's fastball and his change up,  Tim throws his better off-speed pitches more often than Matt, and Tim has had much better control.

By season's end, Matt will likely have improved and Tim will likely have dropped back into the reality of at least the two's in ERA.  But we can see that Tim has clearly outpitched Matt in five areas thus far, resulting in a greater gap between the two than most every expected.