When it comes to player fatigue, first of all, aside from the pitchers and catching positions you should rarely ever during the course of the season bench a player due to fatigue notices or the pregame graphics. So when you do find yourself doing it, it shouldn't be a normal routine moreso a special exception throughout the course of the season. I say so because a regular season will/should have enough other circumstances that cost players game time than fatigue (small or lengthy injuries, performances, transactions are all bigger factors than fatigue). Now bullpen management and starting pitchers is often described at the key job of a manager above all so the wisdom that goes into managing those players use and length of playing time.. is a totally different discussion.
Now, I've simmed full seasons (well 161/162 games) with injuries at the maximum setting and only cpu roster decisions..
*these stats come from 2014
The following field players never missed a single game all year:
Joey Votto 1B Reds - 33HR .309 611AB 106RBI
Ben Zobrist 2B Rays/Nats - .293 100RBI 15HR 634AB
Josh Donaldson 3B A's - 647AB .267 24HR .785OPS
Mark Teixeira 1B Yankees - .908OPS 630AB 32HR 0/0SB lol
Notables* - missing 3 or less games
CUBS S. Castro SS - 160/161 G
O's A. Jones OF - 159/161 G
PIT A. McCuthen OF- 158/161 G
KC N. Aoki OF 159/161 - B. Butler DH 159/161 - E. Hosmer 1B 158/161
SEA R. Cano 2B - 159/161
TEX P. Fielder DH/1B - 158/161
ATL C. Johnson 3B - 158/161
STL M. Carpenter 3B/INF - 158/161
List of Catchers Most Games Played
note*NL Catchers see more Pinch Hitting*
National League - 161 Games
M. Montero (ARI) 148 - .304 477AB
A.J Ellis (LAD) 143 - .265 460AB
W. Nieves (PHI) 141 - .247 377AB
Y. Grandal (SD) 138 - .237 447AB
W. Castillo (CHI) 137 - .265 452AB
American League - 161 Games
J. Castro (HOU) 136 - .267 495AB
S. Perez (KC) 135 - .307 498AB
B. McCann (NYY) 131 - .258 466AB
J. Arencibia (TEX) 129 - .230 440AB
M. Zunino (SEA) 124 - .239 435AB
**B. Posey (SF) 153 Plays some 1B.. (Hector Sanchez 116 G)
** J. Pacheco (COL) 145 Plays other positions (W. Rosario 47G [Broken Hand DL] M. McKenry 77G)
**R. Doumit (ATL) 139* Plays other positions.. (E. Gattis 91G)
** J. Pinto (MIN 120)* Mainly a DH (K. Suzuki 100+G)
To go with that, miraculously to me one team did manage to go wire to wire with their starting rotation in the year. I don't know where an accomplishment like this would rank historically ie: if this is a common occurance or not..
(Bear in mind I also had pitching and reliever stamina tuned to 0 along with those injury settings. The wisdom behind that is assuming it would rely on individual stamina and durability ratings for the pitchers.)
Seattle Mariners 161 G - 4.07 Team ERA (17th) [7CGs 9SOs]:
F. Hernandez 33 GS 9-7 2.83 ERA
H. Iwakuma 32 GS 9-11 3.64 ERA
E. Ramirez 32 GS 14-9 4.22 ERA
T. Walker 32 GS 12-10 4.82 ERA
C. Young 32 GS 9-10 3.69 ERA
Closest Team to get near that mark is ATL but Julio Tehran apparently has a couple of issues.
Every other team, due to various reasons was unable to come near this type of statistical feat.
Hopefully these examples will guide you in terms of how you are willing to manage your players. Again just note that my simulated season has maximum injury impact and the adjustments to pitcher stamina global sliders.