Super Baseball Simulator 1000 for SNES is based on the 1990 statistics.
Just want to say about these Astros, that they were one of the hardest to figure out as none of their stats are relative to their real-life 1990 stats (like the case for the rest of the teams).
Edit – After further inspection, despite being labeled as ‘HOUSTON’, this is actually the 1990/1991 San Francisco Giants. Which makes sense considering the game has the top three teams from each division and the only team ‘excluded’ is San Francisco in the NL West. Thanks to Baseball Reference we can confirm the stats match up to the 1991 San Francisco Giants roster.

Kevin Mitchell struggled to stay healthy throughout his career, but was lucky enough to do so in 1989 and had a monstrous season with 47 home runs 125 RBI .635 slugging percentage 1.023 OPS and 345 TB – leading the league in each statistic.
1991 Houston Astros (San Francisco Giants) Batting Order
1 JIM (Mike Felder). Bats left. St of 2. Center Fielder. .288 average, 5 home runs, 12 running, 6 fielding
2 OREL (Robby Thompson). Bats right. St of C. 2nd Baseman. .251 average, 17 home runs, 8 running, 8 fielding
3 LENY (Will Clark). Bats left. St of 5. 1st Baseman. .290 average, 21 home runs, 7 running, 10 fielding
4 TODD (Kevin Mitchell). Bats right. St of 7. Left Fielder. .286 average, 38 home runs, 6 running, 7 fielding
5 NORM (Matt Williams). Bats right. St of 1. 3rd Baseman. .292 average, 35 home runs, 7 running, 9 fielding
6 OSCR (Kevin Bass). Bats left. St of 4. Right Fielder. .222 average, 5 home runs, 8 running, 8 fielding
7 PETE (Jose Uribe). Bats right. St of 2. Short Stop. .252 average, 4 home runs, 8 running, 9 fielding
8 RCDO (Steve Decker). Bats right. St of 1. Catcher. .286 average, 6 home runs, 4 running, 7 fielding
PH SKIP (Terry Kennedy). Bats left. St of 6. .266 average, 3 home runs, 7 running, 6 fielding
PH ROY (Willie McGee?). Bats left. St of 5. .292 average, 2 home runs, 8 running, 6 fielding
PH FELX (Rick Parker?). Bats right. St of 7. .235 average, 4 home runs, 8 running, 7 fielding
PH WLBR (Dave Anderson). Bats right. St of 8. .341 average, 2 home runs, 8 running, 8 fielding
1991 Houston Astros (San Francisco Giants) Pitching Staff
SP ALEX (Scott Garrelts). Right Hander. 4.25 ERA. SPD 88, R7, L6, F5, ST30
SP BO (John Burkett). Right Hander. 3.88 ERA. SPD 86, R8, L8, F6, ST32
SP CHRS (Kelly Downs?). Right Hander. 3.41 ERA. SPD 93, R5, L4, F3, ST30
SP DARL (Trevor Wilson). Left Hander. 4.04 ERA. SPD 88, R9, L10, F7, ST34
RP ELDN (Jeff Brantley). Right Hander. 1.58 ERA. SPD 89, R6, L5, F4, ST18
Closer FRCS (Dave Righetti). Left Hander. 3.67 ERA. SPD 91, R6, L12, F7, ST20
1991 San Francisco Giants Team Analysis : Yea, they’re the San Francisco Giants, not ‘Houston’. The Giants actually have a good #2 hitter in Robby Thompson, but Mike Felder at leadoff is mediocre (fast, but not as fast as most leadoff hitters). 6-8 and the bench are bad, but the meat of the order has muscle comparable to the strongest offenses in the league. TODD and NORM (Kevin Mitchell and Matt Williams) have immense power, hitting 73 HR’s between them. Will Clark is no slouche hitting at #3 either – less power but a better hitter.
Poor starting pitching though. Garrelts is a classic from RBI Baseball but symbolizes the problem with the Giant’s starting pitching – subpar Stamina and average speed. The #4 starter Darl (Trevor Wilson??) is one of the better pitchers on the team with the highest stamina and decent movement. Righetti is a solid closer and along with Brantley provide some good ST for relievers, and you’ll need it.