Jerick McKinnon is out for the year, and that changes the 49ers’ offense significantly

San Francisco 49ers head coach Kyle Shanahan hand-selected Jerick McKinnon as the ideal running back for his offense this past offseason, signing him to a four-year, $30 million deal despite his limited production with the Minnesota Vikings. Throughout the offseason, we got a better picture of McKinnon’s role in Shanahan’s offense: that of a hard-nosed runner who catches a whole lot of passes.

Now that’s not going to happen, at least not in 2018. McKinnon tore his ACL on the final play of the team’s practice on Saturday. He was placed on injured reserve on Monday and is out for the season. He likely won’t be back to full strength by this time next year.

Although McKinnon isn’t a huge name, his injury affects the 49ers’ offense on a fundamental level — and that’s bad news for the team hoping to keep pace with the acquisition-heavy Los Angeles Rams in the NFC West.

What other running backs do the 49ers have?

The 49ers currently have three running backs on the 53-man roster: Matt Breida, Alfred Morris, and Raheem Mostert.

Breida figures to be the starter, but he’ll likely share the load with Morris, a much more known commodity. As a rookie in 2017, Breida had 105 carries for 465 yards and two touchdowns, with 36 receptions for 180 yards and another touchdown.

Morris, 29, has been an effective running back — at times. He started his career with Washington in 2012, when he put up 1,613 yards and 13 touchdowns on the ground under Shanahan, then an offensive coordinator. Morris eclipsed 1,000 yards rushing the next two seasons as well, and had 547 yards in 115 carries for the Dallas Cowboys last season.

The 49ers only signed Morris prior to the start of the third preseason game. Morris then carried the ball 17 times for 84 yards against the Indianapolis Colts in his 49ers’ debut. He looked awfully good, too:

Morris also started the 49ers’ final preseason game, but didn’t see much playing time, likely so the 49ers could play guys less secure on the depth chart.

Mostert is primarily a special teams contributor. The 26-year-old had just six rushing attempts for 30 yards last season with the 49ers in 2017.

None of those players can match McKinnon’s versatility, however.

Where the 49ers will miss McKinnon most is in the passing game

The 49ers brought in McKinnon this year and Kyle Jusczcyk the year before because that’s the kind of offense Shanahan wants to run — one that asks for, above all else, utility from its players.

In addition to his 570 yards rushing, McKinnon caught 65 passes last year with the Vikings. Of those, 51 came in the regular season, for a total of 421 yards and a pair of touchdowns. He caught another 14 passes for 92 yards in the postseason. He’s fast, shifty, and can also run the ball up the gut. He’s everything Shanahan wanted in a running back short of top guys like Le’Veon Bell or Devonta Freeman.

For his entire NFL career, Morris has just 57 receptions for 421 yards and no touchdowns. So, McKinnon had the same amount of receiving yardage in the 2017 regular season that Morris had in his first six seasons.

Last year, 49ers running backs caught 113 passes and were targeted 165 times. Breida, who backed up Carlos Hyde, ended up with 21 of those catches for 180 yards. He should see even more targets this year, but expecting Breida to pick up all the slack is a lot for an undrafted guy in his second year — especially one coming off a shoulder injury in the preseason.

McKinnon’s injury could affect Jimmy Garoppolo’s comfort factor

Don’t forget about Jimmy Garoppolo and the fact he has been drilling this offense all offseason, preparing for his first regular-season action as a full-time starter. And then one of his biggest weapons goes down right a week before their first game.

While this doesn’t doom the 49ers or Garoppolo, such a loss has to weigh on the newly minted franchise quarterback who received a $137.5 million contract this offseason.

Garoppolo is the face of the 49ers, especially after he finished the 2017 season by winning all five of his starts. He completed 120 of 178 passes for 1,560 yards and seven touchdowns last season, and looked good in limited preseason action this year. Expectations are high for him, and they were rising for the 49ers, too.

There’s no guarantee McKinnon would have been great for the 49ers this season. But he was such a perfect fit for what Shanahan is trying to accomplish on offense that finding success got a lot harder when the 49ers lost him before the season even began.