more about an outfielder's throwing arm than infielder assists do. In recent years, some sabermetricians have begun referring to assists by outfielders as baserunner kills. Some sabermetricians are also using baserunner holds as a statistic to measure outfield arms. A baserunner hold occurs when the baserunner does not attempt to advance an extra base on an outfielder out of concern of being thrown out by a strong, accurate throw. This can be combined with baserunner kills for better accuracy, as runners often do not try for an extra base when an outfielder with an excellent arm is playing. All-time single-season assists leaders by position First base Albert Pujols: 185 (St. Louis Cardinals, 2009) Bill Buckner: 184 (Boston Red Sox, 1985) Mark Grace: 180 (Chicago Cubs, 1990) Mark Grace: 167 (Chicago Cubs, 1991) Sid Bream: 166 (Pittsburgh Pirates, 1986) Bill Buckner: 161 (Chicago Cubs, 1983) Bill Buckner: 159 (Chicago Cubs, 1982) Bill Buckner: 157 (Boston Red Sox, 1986) Todd Helton: 156 (Colorado Rockies, 2003) Mickey Vernon: 155 (Cleveland Indians, 1949) Career Eddie Murray: 1865 Todd Helton: 1728 Jeff Bagwell: 1703 Keith Hernandez: 1682 Mark Grace: 1665 George Sisler: 1529 Mickey Vernon: 1448 Fred McGriff: 1447 Albert Pujols: 1429 Andrés Galarraga: 1376 Fred Tenney: 1363 Bill Buckner: 1351 Jake Beckley: 1315 Second base Frankie Frisch: 641 (St. Louis Cardinals, 1927) Hughie Critz: 588 (Cincinnati Reds, 1926) Rogers Hornsby: 582 (New York Giants, 1927) Ski Melillo: 572 (St. Louis Browns, 1930) Ryne Sandberg: 571 (Chicago Cubs, 1983) Rabbit Maranville: 568 (Pittsburgh Pirates, 1924) Frank Parkinson: 562 (Philadelphia Phillies, 1922) Tony Cuccinello: 559 (Boston Braves, 1936) Johnny Hodapp: 557 (Cleveland Indians, 1930) Lou Bierbauer: 555 (Pittsburgh Pirates, 1892) Shortstop Ozzie Smith: 621 (San Diego Padres, 1980) Glenn Wright: 601 (Pittsburgh Pirates, 1924) Dave Bancroft: 598 (Philadelphia Phillies/New York Giants, 1920) Tommy Thevenow:597 (St. Louis Cardinals, 1926) Iván DeJesús: 595 (Chicago Cubs, 1977) Cal Ripken: 583 (Baltimore Orioles, 1984) Whitey Wietelmann: 581 (Boston Braves, 1943) Dave Bancroft: 579 (New York Giants, 1922) Rabbit Maranville: 574 (Boston Braves, 1914) Don Kessinger: 573 (Chicago Cubs, 1968) Third base Graig Nettles: 412 (Cleveland Indians, 1971) Graig Nettles: 410 (New York Yankees, 1973) Brooks Robinson: 410 (Baltimore Orioles, 1974) Brooks Robinson: 405 (Baltimore Orioles, 1967) Harlond Clift: 405 (St. Louis Browns, 1937) Mike Schmidt: 404 (Philadelphia Phillies, 1974) Doug DeCinces: 399 (California Angels, 1982) Brandon Inge: 398 (Detroit Tigers, 2006) Clete Boyer: 396 (New York Yankees, 1962) Mike Schmidt: