Do Batters Try to Hit Sacrifice Flies?

Conversation overheard at Skaket Beach, Cape Cod, in August, 2005:

“…and I hate the strategy of walking the bases full to set up a force out. It puts so much pressure on the pitcher. Also, don’t hitters bat a lot better with the bases loaded?”
“Well, yes, they do, but most of that comes from sac flies. If sac flies are counted as an ordinary out, as they should be, batters don’t hit any better with the bases loaded.”
“Sac flies ordinary outs? Don’t you think hitters try to hit a fly ball to drive in the runner from 3rd? You know, get some good wood on the ball and drive it out of the infield.”
“Don’t you think they try to do that in all their at-bats?”
“Good point. Wanna play some catch?”

Do Batters Try for Sacrifice Flies?

So, I got to wondering if batters actually do try to hit a fly ball to score the runner from 3rd with less than 2 outs. Do they really try to lift the ball more, trying to get a fly ball instead of a grounder? Can batters control the bat that well, shifting the ball-bat impact point by a fraction of an inch? I tried to investigate these matters by looking at play-by-play data available at Retrosheet.

Methodology

Using data from 2003 and 2004, I considered all players who had at least one sacrifice fly opportunity (SF Opp), meaning a plate appearance with a runner on third base and less than two outs. I did not consider any plate appearances that resulted in an intentional walk or a hit batter. I also ignored bunts, since they have nothing to do with sacrifice flies. There are more than 19,800 plate appearances in the sacrifice fly sample. For each player, I looked at how many times they hit a fly ball (F), a line drive (L), a ground ball (G) or a pop up (P). I also kept track of how many strikeouts (K), non-intentional walks (BB) and home runs (HR) each player had during his sacrifice fly opportunitiess. To compare to non-sac fly situations, I calculated the expected number of each outcome (F, L, etc.) based on how that player performed in all situations (excluding IBB, HBP and bunts), not just sacrifice fly opportunities. The procedure is most easily understood with an example.

In this period, Derek Jeter came to the plate with a runner on third and less than two outs 49 times and he hit seven fly balls (see table below). Looking at all Jeter’s plate appearances in this period, we find he hit 242 fly balls in 1233 plate appearances, for a fly ball rate of 19.6%. So, his expected number of fly balls hit in his sacrifice fly opportunities is simply this rate times the number of opportunities, or 9.6 expected fly balls (49 * (242/1233) ). So, Jeter actually hit fewer fly balls in his sacrifice fly opportunities than he would normally hit.

           SF Opps    Fly Balls     All Opps    Fly Balls 
Jeter, D      49           7           1233       242

I did the same thing for each of the other outcomes and repeated the exercise for all players.

A Look at Some Individual Players

So, do any players show a marked improvement in hitting fly balls in sacrifice fly opportunities? Here are the top guys:

Name        --- F ---   --- L ---   --- G ---   --- P ---   --- K ---   --- BB --   --- HR --
Cabrera,O  26  16  10  11  10   1  21  26  -5   6   7  -1   3   6  -3   2   5  -3   0   1  -1
Loretta    26  17   9  12  13  -1  19  21  -2   3   3   0   3   5  -2   2   5  -3   0   1  -1
Abreu      27  18   9  18  16   2  30  29   1   1   1  -0  13  17  -4   7  15  -8   4   3   1
Winn       20  12   8  14  10   4  20  29  -9   1   3  -2  11  11   0   4   5  -1   3   1   2
Infante    14   6   8   3   4  -1   6   8  -2   1   2  -1   3   5  -2   1   2  -1   2   1   1
Dye        20  12   8   3   7  -4  13  16  -3   3   5  -2  13  12   1   5   5   0   1   2  -1

This table has lots of numbers, but it’s really not that complicated. (Remember “F” is fly ball, “L” is line drive, “G” is ground ball and “P” is pop up.) The headings in the first row are simply the different categories considered. For each category, three numbers are shown: the actual number recorded in sacrifice fly opportunities, the number expected (rounded off) and the difference between the two. So, Orlando Cabrera hit 10 more fly balls than expected (3rd column under the “F” heading). Note that he hit only 5 fewer ground balls, so some of his extra fly balls are coming from reduced strikeouts (3 compared to 6 expected) and walks (2 compared to 5). We will see that this is a general trend. Note that Bobby Abreu got all his extra fly balls from the strikeout and walk columns.

Here are the hitters who hit the fewest fly balls (compared to expected):

Name       --- F ---   --- L ---   --- G ---   --- P ---   --- K ---   --- BB --   --- HR --
Lowell    15  26 -11  15  15   0  25  24   1  13   8   5  12  12   0  13   8   5   4   5  -1
Glaus      3  10  -7   7   5   2  17  11   6   2   3  -1  10   9   1   4   5  -1   0   2  -2
Cameron   10  16  -6  12   8   4  12  14  -2   1   4  -3  20  15   5   9   7   2   1   3  -2
Lawton     6  12  -6  12   8   4  29  20   9   1   3  -2   2   7  -5   5   6  -1   2   2   0
Stairs     6  12  -6  10   6   4  17  18  -1   5   4   1  12  10   2   6   6   0   1   3  -2

It looks like the worst guys are just as bad as the best guys are good. There are several other interesting questions you could ask: Who “enlarges the strike zone” the most, by taking fewer walks in the sacrifice fly opportunities? (Abreu) Who cuts down his swing the most to avoid striking out? (Rocco Baldelli) Who over-adjusts and instead of hitting fly balls ends up popping out more? (Johnny Damon)

Here’s a look at a couple of interesting players:

Name       --- F ---   --- L ---   --- G ---   --- P ---   --- K ---   --- BB --   --- HR -- 
Dunn      11  12  -1   3   8  -5  13  12   1   9   4   5  17  18  -1  11   9   2   5   4   1
Bonds      9   7   2   6   6   0  10   8   2   2   3  -1   0   3  -3   7   7   0   4   3   1

Adam Dunn, you may recall received criticism during the season for never getting any sacrifice flies. Looking at his numbers, it appears that he does not change his hitting approach in sacrifice fly situations, at least as far as walking and striking out are concerned. He does seem to have hit more than his share of pop-ups, but the sample is very small. He actually had 4 sacrifice flies during these opportunities, a number reduced by the fact that almost 50% of the fly balls he hit went for home runs, whereas a typical number is 10-12%. (“That Dunn sure sucks. Keeps hitting home runs instead of sacrifice flies!”) The numbers for Barry Bonds are rather meager, mainly because his many intentional walks are not considered here. It’s tempting to say that Bonds’ approach in sac fly situations is excellent (reduced Ks, no loss of power), however the very small sample size really precludes any meaningful statement.

General Results

Next, to see if there is a general effect, I summed up the contributions of all players and compared the sacrifice fly opportunities case to the general case:

             Fly     LD     GB    Pop      K     BB
All Opps:   4193   2802   6555   1200   3426   1624
 SF Opps:   4422   2667   6951   1215   3021   1520
    Diff:    229   -135    396     15   -405   -104
Diff Pct:    5.5   -4.8    6.0    1.3  -11.8   -6.4

The first row has been scaled to the number of sacrifice fly opportunities so a direct comparison can be made. The biggest relative change in any category is in strikeouts, which are reduced by about 12%. So, it seems batters are indeed trying to make better contact. There are also fewer walks (6% reduction), which also increases the balls in play, which in turn will drive a larger proportion of the runners home. Looking at the batted ball types, we see that both fly balls and ground balls have increased and at essentially the same rate: a 5.5% increase in fly balls and a 6.0% increase in ground balls. Another thing to note is that despite the extra balls in play, there are actually 5% fewer line drives hit in sacrifice fly opportunities, so perhaps some of the fly balls are coming at the expense of line drives. The numbers seem to suggest that batters are expanding their strike zones a little (fewer unintentional walks) and are emphasizing contact (fewer strikeouts), while giving up some power (fewer line drives). The result is more balls in play, but the increase is about the same for fly balls and ground balls.

Note that these categories are all “defense-independent”, meaning they are only influenced by the batter and the pitcher; the defense doesn’t enter the picture. This is an important consideration, since the defensive alignment in sacrifice fly opportunities is much different than it is in general situations: infielders will often play in and outfielders may play much closer as well, especially in tight games.

Conclusions and a Coda

So, as a group batters do seem to be able to change their approach at the plate to increase the probability of getting a fly ball to score a run in a sacrifice fly situation. However, the increase in fly balls comes simply from putting more balls in play (by striking out and walking less often) and not by batters putting more of their batted balls into the air.

How many extra sacrifice flies result from the extra fly balls? Here is a table of how often each type of batted ball results in a sac fly:

+------------+------+------+-------+
| Ball type  | SF   | Opps | Rate  |
+------------+------+------+-------+
| F          | 2666 | 4422 | 0.603 |
| L          |   16 | 2667 | 0.006 |
| P          |   12 | 1225 | 0.010 |
+------------+------+------+-------+

I was surprised by the low number of sacrifice flies off line drives, but this is what the play-by-play data tells us. Part of the reason is that about 75% of line drives go for base hits and hence do not produce a sacrifice fly. In any case, about 60% of fly balls will score a runner from 3rd with less than 2 outs, so the 229 extra fly balls result in about 137 extra sacrifice flies. One may ask, though, if there is some price to pay for the modified approach. We’ve already seen that hard hit balls (line drives) are reduced in sacrifice fly opportunities. Well, this will be the subject of a later analysis, but I’ll leave you with one more comparison, the “biggest” defense-independent outcome of them all:

              Fly    HR   
All Opps:    4193   603
 SF Opps:    4422   507
    Diff:     229   -96
Diff Pct:     5.5 -15.9

In other words, despite the increase in fly balls, the number of home runs is down significantly. We’ll look at this more closely in the next installment.