Should pitchers start once a week?

In Japan they do.  In the Major Baseball League (MBL) they usually start every fifth day.  Yesterday the New York Yankees broke the bank by giving Masahiro Tanaka a seven year contract for $155 million, about $22 million per year.  Tanaka has never pitched in the MBL.  Would the Yankees get more bang for their buck by pitching Tanaka on the same schedule that he had in Japan?  That would mean several fewer starts, maybe 24 instead of 32.

Heavy Load in Japan, but a Star Is Used to It
JAN. 22, 2014  The New York Times
By BENJAMIN HOFFMAN

Masahiro Tanaka ... In terms of pitches per start over the last five seasons, he narrowly beats Justin Verlander, the major league leader in that time span, 113.5 to 112.9, according to the website NPB Tracker.

 In those five seasons he exceeded 125 pitches in a game 29 times. Verlander did the same thing 18 times in that period, and no other major league pitcher did it more than 10.

On the other hand, Tanaka averaged only 24 starts the last five years, partly because Japanese teams play fewer games. In the last five years, Verlander started 169 games. So in that respect, Tanaka has had a lighter load...

Tanaka ... in last year’s Japan Series ... threw an absurd 160 pitches in a Game 6 loss, and 15 more pitches the next day to save Game 7...

The most recent example is another Japanese pitcher, Yu Darvish of the Texas Rangers. In his last three seasons in Japan, Darvish averaged more than 120 pitches a start. But in his two seasons since then, both with the Rangers, he has seemed no worse for the wear, finishing second in the American League Cy Young race last season. Darvish has still been a workhorse by American standards, averaging 108 pitches a start and throwing more than 120 pitches eight times.
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What's obviously missing is the total number of pitches.  Here are the estimates:

	Verlander	Verlander	Darvish	Darvish	Darvish	Tanaka	Tanaka
	starts	113.5					112.9
2009	35	3,973	23	2,760	120	24	2,710
2010	33	3,746	25	3,000	120	20	2,258
2011	34	3,859	28	3,360	120	27	3,048
2012	33	3,746	29	3,132	108	22	2,484
2013	34	3,859	32	3,456	108	28	3,161
		19,182		15,708			13,661
		2009	2011	9,120			8,016

Verlander threw 5,520 more pitches than Tanaka in those five years in the regular season: 29%.  Each season the order of pitches thrown was Verlander, Darvish, Tanaka.

Darvish threw 1,104 more pitches than Tanaka from 2009 through 2011 when both were in Japan.  And Darvish threw 2,047  more pitches than Tanaka in the five years.

In 2013 Darvish had the ninth best SO per 9 innings in MBL history.

Rank	Player (age that year)	Strikeouts per 9 IP	Year	Throws
1.	Randy Johnson (37)	13.4099	2001	L
2.	Pedro Martinez (27)	13.2047	1999	R
3.	Kerry Wood (21)	12.5820	1998	R
4.	Randy Johnson (36)	12.5590	2000	L
5.	Randy Johnson (31)	12.3453	1995	L
6.	Randy Johnson (33)	12.2958	1997	L
7.	Randy Johnson (34)	12.1187	1998	L
8.	Randy Johnson (35)	12.0589	1999	L
9.	Yu Darvish (26)	11.8903	2013	R
10.	Pedro Martinez (28)	11.7788	2000	R

Tanaka has been trending down in SO per 9 innings: 9.6, 8.8, 7.8.  That's a big red flag.  Did the Yankees know that?

It's my understanding that in Japan Tanaka and Darvish pitched once a week on the same day of the week.  Verlander usually pitched every fifth day.

2013 days of rest, starts, wins-losses, ERA:

Verlander

4 18, 6-7 3.16

5 14, 6-5 4.22

6+ 2, 1-0 0.75

Darvish 

4 18, 7-7 2.88

5 10, 3-2 3.49

6+ 4, 3-0 0.99

Should the Yankees change Tanaka's routine?  Should pitchers start once a week?