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The Boston Globe

Sports

Christopher L. Gasper

Fact is, injuries can cost you a job in sports

49ers quarterback Colin Kaepernick stepped in for the concussed Alex Smith and was brilliant.

AP/File

49ers quarterback Colin Kaepernick stepped in for the concussed Alex Smith and was brilliant.

Job security in professional sports is an oxymoron. It’s more like job insecurity. Athletes look over their shoulders so much that their heads should be able to spin 360 degrees, as in “The Exorcist.”

With the exception of a few franchise players — the Tom Bradys, Kobe Bryants, and Derek Jeters — employers are always on the lookout for someone better, younger, or cheaper, or all of the above.

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One of the oldest clichés in sports is also one of the most mendacious: that a player doesn’t lose a job because of injury. He or she does, and he or she will if the replacement is an upgrade.

One player’s malady always has been another’s opportunity. Nobody knows that better than Patriots quarterback Tom Brady, who went from anonymous backup to Super Bowl MVP in Cinderella fashion in 2001, after Jets linebacker Mo Lewis used Drew Bledsoe as a piñata.

The latest example of this cruel fact of sporting life is the quarterback controversy that has developed with the San Francisco 49ers, who are expected to start second-year man Colin Kaepernick Sunday against the New Orleans Saints instead of incumbent Alex Smith.

Filling in for Smith last Monday night, Kaepernick delivered an eye-opening performance in his first NFL start. Facing a stingy and opportunistic Chicago Bears defense, he completed 16 of 23 passes for 243 yards and two touchdowns in a 32-7 beatdown of Da Bears.

It might not be fair to Smith, who guided the 49ers to a 6-2-1 mark before he suffered a concussion against the St. Louis Rams Nov. 11, but you can’t blame 49ers coach Jim Harbaugh for electing to go with Kaepernick if he believes the kid can be better than Smith.

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The 49ers are a defensively stout team with the best running attack in the NFL. They went to the NFC title game last year and lost in overtime to the New York Giants. The only real question about their team in a quarterback league is at quarterback, where Smith has undergone a metamorphosis from foundering former No. 1 overall pick (2005) to presentable passer.

But he’s still not of the Brady-Aaron Rodgers-Drew Brees-Manning brothers ilk, and Harbaugh knows it. Kaepernick represents the most intoxicating elixir in all of sports: potential. He’s an empty decanter the 49ers can fill with visions of championship champagne. He could be the franchise QB the Niners have lacked since Steve Young retired in 1999 (sorry, Jeff Garcia).

This isn’t Brady-Bledsoe redux. The Patriots were coming off a 5-11 season in 2000, and there were already questions about Bledsoe’s fitness as a franchise QB.

Smith has a higher completion percentage this season than Peyton Manning, Rodgers, or Brady, an NFL-best 70 percent. In the game before he got hurt, Smith set the NFL completion percentage mark for a game (94.7), going 18 of 19 for 232 yards and 3 TDs against Arizona. Earlier this year, he shattered Young’s team record for most passes without an interception, going 249.

The only thing Smith has done to lose his job is get concussed on a hit by former Boston College linebacker Jo-Lonn Dunbar.

The reality is that players losing their job to injury is part of the Darwinian nature of athletics. Deployment of a replacement often can lead to unemployment for the starter.

If coaches strictly adhered to loyalty policies, then we would have been deprived of Brady, Lou Gehrig, and Wade Boggs, among others.

Gehrig’s replacement of Wally Pipp at first base for the 1925 New York Yankees remains the most famous job grab in sports history. Pipp sat out a game with a headache. Gehrig began a streak of playing in 2,130 straight games.

Pipp’s name has become synonymous with being displaced. Patriots coach Bill Belichick joked with wide receiver Wes Welker during a 2009 preseason game that Julian Edelman, who had returned a punt for a score, was going to Wally Pipp him (that joke seems more like a threat now).

Few remember that Pipp was actually a very good player, an excellent defensive first baseman who led the American League in fielding percentage the year before. Pipp twice led the American League in home runs during the Dead Ball Era and drove in 108 runs for the Yankees’ first World Series title team in 1923, second only to some guy named Babe Ruth.

But Gehrig, one of the game’s all-time greats, was simply better.

Boggs may never have become a chicken-munching, Hall of Fame hitting machine for the Red Sox if it weren’t for an injury to Carney Lansford 30 years ago. Lansford, the Red Sox third baseman and reigning AL batting champ, injured his ankle in a collision with Detroit Tigers catcher Lance Parrish while trying to score on an inside-the-park home run in June of 1982.

Sox manager Ralph Houk said of Boggs, a 24-year-old rookie, “We’ll find out about Boggs.”

We certainly did, and the Sox traded Lansford after the season.

More recently, a similar scenario played out at third base for the Sox. The only salvation from the Sox’ dreadful 69-93 season was the emergence of rookie third baseman Will Middlebrooks, who got his shot because of Kevin Youkilis’s balky back. The play of Middlebrooks had more to do with Youk’s trade to the Chicago White Sox than anything that came out of Bobby Valentine’s mouth.

Ray Allen’s ankle injury created a path for Avery Bradley to force his way into the Celtics’ starting lineup and into the team’s group of core players.

What’s playing out by the Bay between Kaepernick and Smith is nothing new. It’s part of the circle of life in sports.

As Smith is finding out, no matter how well you’re playing, job loss is only a play — and a player — away.

Christopher L. Gasper is a Globe columnist and the host of Boston Sports Live. He can be reached at cgasper@globe.com.

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