| Thomas Long | |
| Position: | Right Fielder |
| Birth Date: | November 1860 |
| Birth Place: | Philadelphia, Pennsylvania |
| Death Place: | Norristown, Pennsylvania |
| Bats: | Unknown |
| Throws: | Unknown |
| Debutleague: | MLB |
| Debutdate: | August 29 |
| Debutyear: | 1888 |
| Debutteam: | Louisville Colonels |
| Finalleague: | MLB |
| Finaldate: | August 29 |
| Finalyear: | 1888 |
| Finalteam: | Louisville Colonels |
| Statleague: | MLB |
| Stat1label: | Batting average |
| Stat1value: | .000 |
| Stat2label: | Home runs |
| Stat2value: | 0 |
| Stat3label: | RBI |
| Stat3value: | 0 |
| Teams: | |
Thomas L. Long (November 1860–December 15, 1914) was an American professional baseball player who played one game in the American Association for the 1888 Louisville Colonels as a right fielder. Previously, Long was thought to be among the Major League Baseball players with unidentified given names, but further research revealed that he was Thomas Long, who had previously played in the minor leagues for the Peoria Reds of the Northwestern League in, the Wilmington Blue Hens of the Eastern League in, and a team representing Bradford, Pennsylvania in the Pennsylvania State Association in .[1] In his single game in the major leagues, Long had three plate appearances, walked once, and struck out once.[2]