How has the designated hitter role affected baseball players' careers?

Context: Advocates of the designated hitter point to the extension of many careers it has enabled, and, in a few cases, created long, productive careers for players who are weak fielders or have a history of injuries, such as Cecil Fielder and David Ortiz. Hall of Fame members George Brett, Carl Yastrzemski, Paul Molitor, Harold Baines and Edgar Martínez continued their careers longer than they ordinarily would have without the rule. Barry Bonds, who spent his entire career in the National League and even won eight Gold Gloves earlier in his career, was used strictly as a DH later in his career when the San Francisco Giants played away interleague games because of his diminishing fielding skills. Some believe that extending careers of older players is more of a disadvantage than an advantage, filling spots that otherwise may have been taken by younger players who end up not finding a place in the major leagues.

Answer: The designated hitter role has extended the careers of baseball players who are weak fielders or have a history of injuries. However, this means they take up team roster spots that otherwise might be filled by younger players.