Santa Clara, Calif. — When Justin Smith decided that his body wouldn't let him perform up to his own lofty standards, he knew it was time to stop playing.
Smith announced Monday that he is retiring after 14 seasons as one of the top defensive linemen in the NFL, dealing yet another blow to the San Francisco 49ers in a rough offseason.
"They all want you to keep playing, and I want to keep playing as well, but when you get on the bald tires, you're on the bald tires," Smith said.
One of the most durable players at one of the most physically demanding positions, Smith had been hampered the past two seasons by a bum left shoulder that he first hurt in training camp in 2013.
That shoulder absorbed the brunt of the punishment as a right defensive end going up against 300-pound linemen all game and Smith did not feel up to playing another season.
"It doesn't respond like I want it to respond anymore," he said. "If you don't have the tools, you can't do the job. It's time to go."
While Smith could still be an effective player, he could no longer be the dominant one he had been for so long in his career and that's what led to his decision.
"People are going to compare him to everybody else," coach Jim Tomsula said. "Justin Smith doesn't compare himself to anybody else. He compares himself to himself. That's the bar he sets. … I've always known with Justin that if he didn't feel like health-wise he can play at the level he plays at, he's not going to do it."
Smith had just two sacks in the final 14 games last season as his practice time, snap count and effectiveness dwindled toward the end of the season.
Smith is the third defensive star to retire from the 49ers this offseason, joining linebackers Patrick Willis and Chris Borland. Coach Jim Harbaugh is also gone, along with running back Frank Gore, guard Mike Iupati, receiver Michael Crabtree, linebacker Dan Skuta and cornerbacks Chris Culliver and Perrish Cox.
Smith played 14 seasons in the NFL after being drafted in the first round by Cincinnati in 2001. After seven successful seasons with the Bengals, he signed as a free agent in San Francisco and had his best success in seven years with the 49ers.
Smith was the anchor of San Francisco's 3-4 defense that made three straight trips to the NFC title game from 2011-13 and one Super Bowl appearance. He tied up blockers and broke down protection to help the team's stellar linebacker corps of Willis, Navorro Bowman and Aldon Smith succeed.
While Smith never recorded double-digit sacks in a season in his career, he was so well-regarded that he was selected as an All Pro first-team defensive tackle and second-team defensive end in 2011. He was the first player ever to make the AP's first and second team at different positions.
"Justin is the consummate professional whose impact on this organization can never be measured by statistics alone," 49ers general manager Trent Baalke said. "His durability, competitiveness, work ethic, strength and rare stamina helped set him apart over his 14-year career. Cowboy will go down as one of the best to ever wear a 49ers uniform and his candidness, work ethic and pure passion for the game will be missed."
Dolphins extend Tannehill
Ryan Tannehill signed a $77.7 million, four-year extension with the Dolphins that keeps him under contract through 2020.
Last month, the Dolphins exercised their fifth-year, $16.2 million option for 2016 on the quarterback's rookie contract.
The eighth overall pick of the 2012 draft has started every game in his first three seasons and improved each year. Last season he threw for 4,045 yards with 27 touchdowns, and his passer rating was 92.8. All of those figures were career highs.
Tannehill, 26, is the first quarterback from the 2012 draft class — a group that also includes Andrew Luck, Russell Wilson and Robert Griffin III — to sign a long-term deal.
"He is a proven quarterback in this league that combines a talented skill-set with work ethic, passion, toughness, and a team first mentality," Dolphins general manager Dennis Hickey said in a statement. "We are committed and believe in Ryan as our quarterback for the long-term."
The 49ers signed Mylan Hicks, an undrafted cornerback out of Michigan State, to a three-year contract.
... Seahawks reserve defensive tackle Jesse Williams will undergo kidney surgery after being diagnosed with cancer.
... The Cowboys released fullback Jed Collins. Collins signed with the Cowboys during the offseason after leaving the Lions as a free agent.
... The Cardinals signed running back David Johnson and tight end Gerald Christian. Johnson was a third-round pick and Christian was drafted in the seventh round.