San Francisco 49ers T-Shirt , promote Nick Mullens from practice squad The San Francisco 49ers made the formal move of placing Jimmy Garoppolo on injured reserve. In conjunction, they promoted quarterback Nick Mullens from the practice squad. And it would appear that will be it for the time being.The 49ers worked out at least seven quarterbacks on Tuesday. It was a fairly limited group, although given where we are in the season, the number of quality quarterbacks the team is seriously going to consider signing is limited.Head coach Kyle Shanahan told the media on Wednesday that the team was not going to sign any of them for the time being, but would not rule it out for the future. For this week, there are too many roster question marks to consider. They have several players that will be Friday or Saturday decisions, and they canr17;t afford to carry a third quarterback behind C.J. Beathard and Nick Mullens. Shanahan also said they were not looking at any trade possibilities.Beathard returns to the starting role in an improved situation compared to a year ago. The 49ers offensive line remains a work in progress, but theyr17;ve got some consistency on the group. It is improved, and ideally he wonr17;t take nearly as much of a beating. Her17;s got some better pass catchers, and the running game has looked really solid the past two weeks.Most important for Beathard is the fact that he has a full offseason under his belt learning the system. When Shanahan was the Atlanta Falcons offensive coordinator, Matt Ryan took a big step forward in the offense in year two. Ir17;m not here to say Beathard is Ryan, but in his second year in the offense, he would hopefully be in a position to better understand what is going on San Francisco 49ers Hats , and in turn make quicker decisions.Beathard took a beating last year, partially due to his offensive line and partially due to his own rookie status. He is a downgrade from Jimmy Garoppolo, but he needs to show he is an upgrade from what he was a year ago.Breaking down the 49ersr17; running game success against the Chiefs While the 49ers are still reeling from the loss of their franchise quarterback for their season, itr17;s probably to shift some focus over to some positive things about the 49ersr17; offense. Head coach Kyle Shanahan has always prided himself about having a successful run game and San Francisco is delivering on that this season.Even with top running back Jerick McKinnon sidelined for the entire season with a torn ACL, backups Matt Breida and Alfred Morris have seamlessly stepped in, carrying the burden thus far. After three weeks, Breida is tied for the most rushing yards in the NFL, with Cowboysr17; tailback Ezekiel Elliot (274). San Francisco is second in the NFL in rushing yards per attempt (5.6) and second in rushing yards per game (152.7) due to the skill of the running backs, but also in part due to the success of the offensive line. Per Pro Football Focus, 49ersr17; rookie right tackle Mike McGlinchey is having a phenomenal season, posting an 84.7 run-blocking grade against the Chiefs and possessing a run-blocking grade of 79.4 through three weeks r12; which is second in the NFL. Combine that with veteran lineman Joe Staley and Weston Richburg running over defensive linemen and the 49ersr17; running backs have wide open lanes.How wide open, you ask? The 49ers have 230 yards on the ground before they are touched by a defensive player r12; a number thatr17;s second behind Carolina, according to ESPN. Sundayr17;s contest against Kansas City backs that notion up San Francisco 49ers Hoodie , as Breida and Morris broke off big runs, their longest being 26 and 16 yards, respectively.On Breidar17;s biggest run of the day, it was a huge gain due to his creativity on the play. The running lane closes quickly, but the 49ersr17; second-year back has a solid presence of mind to cut it back to the left side of the field, where therer17;s no defenders. That allows Breida to kick it into a higher gear and gain 26 yards on the play.49ers have a lot of success on these misdirection, where they get a wide receiver running across the line of scrimmage to freeze up one of the defensive ends, allowing the blockers to shift in the direction of the run. In this case, it frees up a huge hole for Breida to gain 21 yards. It wasnr17;t until early in the third quarter that the 49ers found some offensive rhythm, especially in their running game. Quarterback Jimmy Garoppolo bobbles this snap, but is able to toss it to Breida, who takes it for a 27-yard gain.On this play, the 49ers offensive line does a solid job run blocking Youth Customized San Francisco 49ers Jerseys , bringing in tight end George Kittle as an extra blocker and allowing fullback Kyle Juszczyk to be the lead blocker. The opening gave way to a six-yard Morris gain on first down. Having positive first downs have been key to sustaining long drives for San Franciscor17;s offense.Another strong example of the 49ers ability to line up and run block. All the linemen up front hold their blocks, creating a lane for Morris to gain nearly 10 yards before first contact. Then Morris is able to use his physicality to turn it into his longest run of the afternoon.I mean, look at this hole created by the 49ersr17; offensive line. You or I could run through that opening for a positive gain. Morris takes that for an easy eight-yard gain and the 49ers have a short second down. Having successful run plays, opens up the dangerous play-action passing game, which is the base of the Shanahan offense.Herer17;s another wrinkle in the 49ersr17; running attack, as Garoppolo hands it to Juszczyk, who has the option of running of the ball or tossing it to Breida. In this case, the 49ersr17; fullback does the correct thing, tossing it to Breida. It eventually turns into a nice red zone gain for the 49ers of 13 yards.No matter whor17;s in the backfield for San Francisco, this offensive line unit is absolutely mauling the defenders and creating wide open running lanes for the backs. Without Garoppolo in the lineup, Ir17;m sure defenses will start to adjust to take away the running game primarily. Defenses should start to stack the boxes with eight defenders and force backup quarterback C.J. Beathard to make throws from the pocket. If the 49ers can continue to run the ball down opposing defensesr17; throats then, Ir17;ll be impressed.