Appendix:Glossary of baseball jargon (O)

OBP

 * On-base percentage.

O-fer

 * A batter who goes hitless in a game, as in "0 for 4" (spoken as "oh for four"). Also wears the collar.

off base

 * Unawares or by surprise, usually in the phrase "caught off base"; OED dates to 1935. Meaning misguided, mistaken, or working on faulty assumptions, this usage dates to 1940. Both these uses derive from the situation of a runner being away from a base and thus in a position to being put out (1872).
 * "The absence of any sharp new angle, any strong new drive in Mr. Roosevelt's messages reflected the fact that he and his Cabinet (only Messrs. Hull. Murphy, Woodring, Edison and Ickes were at hand) had been caught off-base with the rest of the world by the Hitler-Stalin deal, the sudden push for Poland."
 * "Lotte Ulbricht replied that Madame Yang was way off base. No one was demanding that oppressed nations live happily with their oppressors, she said, and added that Russia was, as always, 'wholeheartedly behind the revolutionary struggles of colonial peoples.'"

off-speed pitch

 * A pitch that is significantly slower than a given pitcher's fastball. Typically, a curveball or a change-up.

official game

 * A game that can be considered complete. If more than half the game has been played before being called by an umpire, it is considered "official" and all records from the game are computed in the players' and teams' statistics. For a 9-inning game, five innings need to be played. A game that cannot be considered complete can either be suspended or replayed from the first inning.

official scorer

 * The official scorer is a person appointed by the league to record the events on the field and to send this official record to the league offices. The official scorer never goes on the field during a game (but typically watches from the press box).  The official scorer's judgments do not affect the progress or outcome of the game but they do affect game and player statistics. For example, only umpires call balls and strikes, whether a batted ball is fair or foul, whether a hit is a home run, and whether runners are safe or out.  But it's the official scorer who determines whether a pitch that gets by the catcher is a wild pitch or a passed ball or whether a batted ball is a hit or an error (or a combination of the two), and who gets credited with an error, put-out, or assist.

OFP

 * Overall Future Potential (OFP) is a scouting assessment of a young player's potential as a future major leaguer, scored from 20 to 80. The criteria are different for pitchers and position players. See also tools.

Ol’ Number One

 * The fastball. From the sign the catcher gives for that pitch.

Olympic Rings

 * When a batter strikes out five times in a game. This same dubious achievement may also merit a Platinum Sombrero.

On-base percentage (OBP)

 * Percentage of at-bats where a batter reaches base for any reason other than an error or a fielder's choice.

on-deck

 * The next batter due to bat after the current batter. The area designated for the on-deck batter is a circle 5 feet(1.5 m) in diameter, officially called the "next batter's box" and commonly called the "on-deck circle." Ironically, the on-deck batter rarely stands in the on-deck circle.

on the black

 * The black edge of home plate.


 * A pitch that just nicks the edge of the zone for a called strike.

on the board

 * A team is "on the board" (i.e., the scoreboard) when it has scored one or more runs. "After being shut out for 6 innings, the Sox are finally on the board." White Sox announcer Hawk Harrelson also uses the phrase as part of his home run call: "You can put in the booooard... YES!"

on the "interstate"

 * A player batting between .100 and .199 is said to be "on the interstate." The term refers to the fact that a batting average in the .100s can resemble the abbreviated name of an interstate highway (e.g. .195 resembles "I95"), especially on older scoreboards where the numeral "1" appears identical to the uppercase letter "I" (with no serifs). A hit to put an average above .200 gets a batter "off the interstate." A batter whose average is below .100 is sometimes said to be "off the map". See also Mendoza line.

one-game wonder

 * A player who appears in just one major league game, plays respectably, and then is either demoted to the bench or the minor leagues.

one-hitter

 * A game in which one team was limited to one hit, a great feat for a pitcher. Batters may have reached base via walks, errors, or being hit by a pitch. See also no-hitter and perfect game.

one-two-three inning

 * Side retired in order. Three up, three down.

"Onion"

 * Derisive nickname of the short-lived Union Association.

opener

 * A pitcher who specializes in getting the first outs of a game before being replaced, either by a long reliever or a pitcher who would normally start.

opposite field hit

 * A hit to the "opposite" side of the field from the direction of a player's natural swing, i.e., a left-handed batter who hits to left field or a right-handed batter who hits to right field. Also known as going the other way. See pull hitter.

OPS (On-base Plus Slugging)

 * A term recently invented by statheads to measure of a batter's ability to produce runs. Obtained by adding slugging average and on-base percentage.

out of left field

 * See left field.

outfielder

 * An outfielder is a player whose position is either left field, center field, or right field. See position.

outside corner

 * The location of a strike that travels over the far edge of home plate from the batter.