Dave Koslo

Pitcher · Career Stats, Bio & Records (1941-1955)

Dave Koslo was a pitcher who played in Major League Baseball from 1941 to 1955 for the New York Giants, the Baltimore Orioles, and the Milwaukee Braves, a span of 15 seasons. Across 348 career appearances, he went 92-107 with a 3.68 ERA, 606 strikeouts, and 22 saves. He also batted .109 with 3 home runs. His career Pitcher PIV — Baseball Data Hub's era-adjusted measure of pitching impact — is 4510.2.

W (Wins):
Games credited to a pitcher whose team took a lead it never surrendered while he was the pitcher of record.
ERA (Earned Run Average):
Earned runs allowed per nine innings pitched: (ER × 9) ÷ IP. The primary measure of pitching effectiveness.
SO (Strikeouts):
For a batter, times retired on a third strike; for a pitcher, batters retired on a third strike.
WHIP (Walks and Hits per Inning Pitched):
Baserunners allowed per inning: (BB + H) ÷ IP. Under 1.00 is elite.

Data updated

W–L 92–107
ERA 3.68
WHIP 1.34
SO 606
Pitcher PIV 4510.2
Position
Pitcher
Bats / Throws
L / L
Height / Weight
5'11" / 180 lb
Born
3/31/1920 in Menasha, WI, USA
Died
12/1/1975 in Menasha, WI, USA
MLB Debut
1941-09-12
Last Game
1955-04-14

Full name: George Bernard Koslo

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Career Pitching Statistics

Dave Koslo — Career Pitching Statistics
W L G GS CG SHO SV IP H ER HR BB SO ERA Pitcher PIV
92 107 348 189 74 15 22 1591.1 1,597 651 121 538 606 3.68 4510.2

Career ERA 3.68 vs. league average 3.94 across their career seasons — 6.6% better than league average.

Season-by-Season Pitching

Pitching Career Arc

Click a stat to plot it across every season.

Dave Koslo Stats, Bio & Career Records
Year Team Lg W L G GS CG SHO SV IP H ER BB SO ERA Lg ERA Pitcher PIV
1941 NY1 NL 1 2 4 3 2 0 0 23.2 17 5 10 12 1.90 3.94 (+52%) 522.1
1942 NY1 NL 3 6 19 11 3 1 0 78.0 79 44 32 42 5.08 3.57 (-42%) -716.6
1946 NY1 NL 14 19 40 35 17 3 1 265.1 251 107 101 121 3.63 3.59 (-1%) -111.7
1947 NY1 NL 15 10 39 31 10 3 0 217.1 223 106 82 86 4.39 3.97 (-11%) -2619.2
1948 NY1 NL 8 10 35 18 5 3 3 149.0 168 64 62 58 3.87 4.10 (+6%) 880.6
1949 NY1 NL 11 14 38 23 15 0 4 212.0 193 59 43 64 2.50 4.12 (+39%) 4462.4
1950 NY1 NL 13 15 40 22 7 1 3 186.2 190 81 68 56 3.91 4.36 (+10%) -243.0
1951 NY1 NL 10 9 39 16 5 2 3 149.2 153 55 45 54 3.31 4.04 (+18%) -835.8
1952 NY1 NL 10 7 41 17 8 2 5 166.1 154 59 47 67 3.19 3.70 (+14%) 1948.6
1953 NY1 NL 6 12 37 12 2 0 2 111.2 135 59 36 36 4.76 4.14 (-15%) 759.3
1954 BAL AL 0 1 3 1 0 0 0 14.1 20 5 3 3 3.14 3.90 (+19%) 137.7
1954 ML1 NL 1 1 12 0 0 0 1 17.1 13 6 9 7 3.12 3.90 (+20%) 325.9
1955 ML1 NL 0 1 1 0 0 0 0 0.0 1 1 0 0 0.00 — 0.0
Career · 13 seasons 92 107 348 189 74 15 22 1,591.1 1,597 651 538 606 3.68 — 4,510

Lg columns show the league average for that season, with the player's figure as a percentage above or below it. Career totals the seasons listed above.

Career Batting Statistics

Dave Koslo — Career Batting Statistics
G AB R H 2B 3B HR RBI SB BB SO AVG OBP SLG OPS PIV
350 516 31 56 12 0 3 30 1 36 222 .109 .168 .149 .317 -3,446

Career AVG .109 vs. league average .260 across their career seasons — 58.3% below league average.

Career OBP .168 vs. league average .334 across their career seasons — 49.7% below league average.

Career SLG .149 vs. league average .379 across their career seasons — 60.6% below league average.

Career OPS .317 vs. league average .713 across their career seasons — 55.5% below league average.

Season-by-Season Batting

Career Arc

Click a stat to plot it across every season.

Dave Koslo Stats, Bio & Career Records
Year Team Lg G AB R H 2B 3B HR RBI SB BB SO AVG Lg AVG Lg OBP Lg SLG Lg OPS PIV
1941 NY1 NL 4 9 0 1 0 0 0 0 0 0 7 .111 — — — — 0.0
1942 NY1 NL 19 25 4 3 2 0 0 1 0 2 10 .120 — — — — 0.0
1946 NY1 NL 41 88 7 11 2 0 0 6 0 4 39 .125 .256 (-51%) .328 (-50%) .358 (-59%) .687 (-55%) -746.5
1947 NY1 NL 39 78 6 10 1 0 0 2 0 8 37 .128 .262 (-51%) .336 (-38%) .376 (-63%) .712 (-51%) -623.0
1948 NY1 NL 35 44 2 5 2 0 0 4 0 1 16 .114 — — — — 0.0
1949 NY1 NL 39 69 4 10 2 0 2 7 0 5 27 .145 .262 (-45%) .343 (-41%) .384 (-32%) .727 (-36%) -424.3
1950 NY1 NL 40 65 4 8 1 0 1 6 0 6 24 .123 .265 (-54%) .346 (-43%) .401 (-54%) .747 (-49%) -533.7
1951 NY1 NL 39 50 1 5 1 0 0 1 1 6 18 .100 .260 (-62%) .336 (-42%) .385 (-69%) .721 (-56%) -448.6
1952 NY1 NL 41 54 3 2 1 0 0 3 0 3 31 .037 .252 (-85%) .326 (-73%) .369 (-85%) .696 (-79%) -670.1
1953 NY1 NL 37 30 0 1 0 0 0 0 0 1 11 .033 — — — — 0.0
1954 BAL AL 3 3 0 0 0 0 0 0 0 0 2 .000 — — — — 0.0
1954 ML1 NL 12 1 0 0 0 0 0 0 0 0 0 .000 — — — — 0.0
1955 ML1 NL 1 0 0 0 0 0 0 0 0 0 0 .000 — — — — 0.0
Career · 13 seasons 350 516 31 56 12 0 3 30 1 36 222 .109 — — — — -3,446

Lg columns show the league average for that season, with the player's figure as a percentage above or below it. Career totals the seasons listed above.

Postseason Statistics

Playoff Career Batting

Dave Koslo — Playoff Career Batting
G AB R H 2B 3B HR RBI BB SO AVG
2 5 0 0 0 0 0 0 0 2 .000

Playoff Batting by Year

Dave Koslo — Playoff Batting by Year
Year Round Team G AB R H 2B 3B HR RBI BB SO AVG
1951 WS NY1 2 5 0 0 0 0 0 0 0 2 .000

Playoff Career Pitching

Dave Koslo — Playoff Career Pitching
W L G GS SV IP H ER BB SO ERA
1 1 2 2 0 15.0 12 5 7 6 3.00

Playoff Pitching by Year

Dave Koslo — Playoff Pitching by Year
Year Round Team W L G GS SV IP H ER BB SO ERA
1951 WS NY1 1 1 2 2 0 15.0 12 5 7 6 3.00

Game Log & Splits

View full game log (698 games) →

Per-game data from Retrosheet (regular season, through 2025).

Batting — Home / Away

Dave Koslo — Batting — Home / Away
SplitGABRHHRRBIAVG
Home1682341318211.077
Away1822821838118.135

Pitching — Home / Away

Dave Koslo — Pitching — Home / Away
SplitGIPHERBBSOERA
Home168781.07513232532963.72
Away180810.08463232853173.59

Last 10 Games — Batting

Dave Koslo — Last 10 Games — Batting
DateTmOppResABRH2B3BHRRBIBBSO
1955-04-14 ATLSTLL 000000000
1954-09-19 ATLSTLL 100000000
1954-09-17 ATLSTLW 000000000
1954-09-16 ATLNY1L 000000000
1954-09-11 ATLBROL 000000000
1954-09-05 ATLCINW 000000000
1954-09-04 ATLCINW 000000000
1954-09-03 ATLCINW 000000000
1954-08-29 ATLBROL 000000000
1954-08-29 ATLBROL 000000000

Last 10 Games — Pitching

Dave Koslo — Last 10 Games — Pitching
DateTmOppDecIPHRERBBSOHR
1955-04-14 ATLSTL L 0.0111001
1954-09-19 ATLSTL L 2.2333300
1954-09-17 ATLSTL — 0.1000000
1954-09-16 ATLNY1 — 0.2200000
1954-09-11 ATLBRO — 2.0000110
1954-09-05 ATLCIN SV 1.2100000
1954-09-04 ATLCIN W 2.2200110
1954-09-03 ATLCIN — 1.1000000
1954-08-29 ATLBRO — 2.0433220
1954-08-29 ATLBRO — 0.2000010

Fielding Statistics

Career Fielding Totals by Position

Dave Koslo — Career Fielding Totals by Position
Position G GS PO A E DP
P 348 1 75 307 14 23

Season-by-Season Fielding

Dave Koslo — Season-by-Season Fielding
Year Team Pos G GS PO A E DP
1941 NY1 P 4 0 0 3 1 0
1942 NY1 P 19 0 1 13 1 0
1946 NY1 P 40 0 10 61 3 1
1947 NY1 P 39 0 13 36 2 2
1948 NY1 P 35 0 8 24 0 1
1949 NY1 P 38 0 7 39 0 4
1950 NY1 P 40 0 5 37 2 3
1951 NY1 P 39 0 7 38 0 2
1952 NY1 P 41 0 16 33 4 7
1953 NY1 P 37 0 7 22 1 3
1954 BAL P 3 1 1 1 0 0
1954 ML1 P 12 0 0 0 0 0
1955 ML1 P 1 0 0 0 0 0

Career Games by Position

Position Diamond

Circle size = games played at each position.

Dave Koslo Stats, Bio & Career Records
Position Games
Pitcher 348

Most Similar Players

Career comps based on counting + rate stats and primary position. Score is relative — closest peer anchors at ~98%.

Career Spans

Dave Koslo (highlighted) compared to peers across the same era.

  1. 98
    Johnny Morrison
    103-80, 3.65 ERA
  2. 96
    Al Smith
    99-101, 3.72 ERA
  3. 92
    Nels Potter
    92-97, 3.99 ERA
  4. 85
    Jack Scott
    103-109, 3.85 ERA
  5. 84
    Roger Craig
    74-98, 3.83 ERA
  6. 76
    Art Houtteman
    87-91, 4.14 ERA

Dave Koslo: the record in brief

Dave Koslo's major league career runs from a debut on September 12, 1941 to a final game on April 14, 1955. The team column moves through the New York Giants (1941 through 1953), the Baltimore Orioles (1954), and the Milwaukee Braves (1954 through 1955). The bio lists Koslo as a pitcher who batted and threw left-handed. Height and weight on file: 5-foot-11 and 180 pounds. Koslo was born on March 31, 1920, in Menasha, WI, USA. Koslo died on December 1, 1975, in Menasha, WI, USA. The bio lists the given name George Bernard.

The pitching table credits Koslo with a 92-107 record and a 3.68 ERA in 348 games. The totals include 606 strikeouts, 74 complete games, 15 shutouts, and 22 saves. That 3.68 ERA compares with a 3.94 league average across the same seasons, 6.6% better. 1947 brought Koslo a season-high 15 wins. Koslo struck out 121 batters in 1946, a career high.

Frequently Asked Questions about Dave Koslo

What years did Dave Koslo play?
Dave Koslo played in Major League Baseball from 1941 to 1955.
Was Dave Koslo a pitcher?
Yes. Dave Koslo pitched in the major leagues, recording 92 wins and 606 strikeouts.
How many home runs did Dave Koslo hit?
Dave Koslo hit 3 career home runs with 56 hits.
What teams did Dave Koslo play for?
Dave Koslo played for 3 teams: the New York Giants (1941–1942, 1946–1953), the Baltimore Orioles (1954), and the Milwaukee Braves (1954–1955).
What were Dave Koslo's career stats?
In 348 games, Dave Koslo went 92-107 with a 3.68 ERA, 606 strikeouts, 1,591.1 innings pitched, and 22 saves. At the plate he had 56 hits and 3 home runs.
What position did Dave Koslo play?
Dave Koslo played primarily as a pitcher, the position where he appeared in the most games.
How tall was Dave Koslo and how much did he weigh?
Dave Koslo was listed at 5 feet 11 inches and 180 pounds.
What was Dave Koslo's career ERA?
Dave Koslo finished with a 3.68 career ERA, going 92-107 with 606 strikeouts.
How many strikeouts did Dave Koslo have?
Dave Koslo recorded 606 career strikeouts.
Is Dave Koslo in the Hall of Fame?
No. Dave Koslo has not been inducted into the National Baseball Hall of Fame.