November 13, 1989: Jeff Schaefer was signed as a free agent by the Mariners.[1]
Regular season
June 2, 1990: Randy Johnson threw a no-hitter versus the Detroit Tigers.[2] Johnson was the first Mariner to throw a no-hitter. He was also the tallest pitcher in Major League history to throw a no-hitter. It was the 2101st game in Mariners history.
September 4, 1990: Ken Griffey Sr. and Ken Griffey, Jr. hit back-to-back home runs in a game against the California Angels. It was the first and only time in Major League Baseball history that this ever happened.
Ken Griffey, Sr. joined his son Ken Griffey, Jr. to become the first father and son to play in a game together. The game was played against the Kansas City Royals on August 31. The Griffeys became the first father-and-son teammates. He also hit back-to-back home runs with his son on September 14, 1990.
Line Score
August 31, Kingdome, Seattle, Washington
Team
1
2
3
4
5
6
7
8
9
R
H
E
Kansas City
0
2
0
0
0
0
0
0
0
2
6
2
Seattle
3
0
0
0
1
0
1
0
x
5
10
1
W: Johnson (13-8) L: Davis (7-10)
Home Runs: Pecota (4) Attendance: 27,166 Time: 2:27
Batting
Kansas City Royals
AB
R
H
RBI
Seattle Mariners
AB
R
H
RBI
Seitzer, 3b
4
0
0
0
Reynolds, 2b
5
0
1
0
McRae, cf
4
0
1
0
Griffey, lf
4
1
1
0
Tartabull, dh
3
0
1
0
Griffey, Jr., cf
4
1
1
0
Jackson, lf
3
1
1
0
Davis, dh
2
3
2
1
Macfarlane, c
4
0
1
0
O’Brien, 1b
3
0
0
0
Eisenreich, rf
3
0
0
1
Buhner, rf
3
0
2
1
Pecota, 1b
3
1
1
1
Martinez, 3b
2
0
1
1
White, 2b
3
0
1
0
Schaefer. 3b
2
0
1
1
Jeltz, ss
3
0
0
0
Bradley, c
4
0
1
0
NONE
0
0
0
0
Vizquel, ss
3
0
0
0
Totals
30
2
6
2
Totals
32
5
10
4
Pitching
Kansas City Royals
IP
H
R
ER
BB
SO
Davis L (7-10)
6.2
9
5
4
6
1
Sanchez
1.1
1
0
0
0
0
Totals
8.0
10
5
4
6
1
Seattle Mariners
IP
H
R
ER
BB
SO
Johnson W (13-8)
7.1
5
2
2
2
4
Swift SV (3)
1.2
1
0
0
0
0
Totals
9.0
6
2
2
2
4
Player stats
= Indicates team leader
Batting
Starters by position
Note: Pos = Position; G = Games played; AB = At Bats; H = Hits; Avg. = Batting Average; HR = Home Runs; RBI = Runs Batted In
^Johnson, Lloyd, and Wolff, Miles, ed., The Encyclopedia of Minor League Baseball, 2nd and 3rd editions. Durham, North Carolina: Baseball America, 1997 and 2007