The San Francisco 49ers know it's not wise to me s around with the health of franchise players.That is precisely why they are likely going to keep their superstar running back out for the entirety of preseason.On Tuesday, ESPN's Nick Wagoner San Francisco's perennial MVP candidate Christian McCaffrey has suffered a calf strain that will keep him out of action for a bit."Christian McCaffrey has a calf strain," Wagoner said. "He is unlikely to participate in this preseason, per Kyle Shanahan. He's likely to mi s a couple DJ Ivey Jersey of weeks of practice, also."McCaffrey, 28, has had perhaps the most eventful offseason of his career thus far. Mere months after falling just short of a Super Bowl victory, McCaffery got married. He was also named the for Madden 25 this summer.McCaffery is known for taking meticulous care of his body, so an injury like a calf strain shouldn't do much to affect his readine s for the regular season.San Francisco hosts the New York Jets on September 9 to open the NFL regular season. It's a date that McCaffrey has certainly had circled on his calendar for some time.More NFL: Elijah Deveaux Jersey