The 49ers have been in Houston this week for joint practices and will play the Texans tonight at NRG Stadium. The top battles heading into training camp were arguably guard, wide receiver, and linebacker. Injuries from this past week add to that list, and have allowed players fighting for jobs the opportunity to earn a spot.

The 49ers' top two running backs, Jerick McKinnon and Matt Breida, will most likely be out of action until Week 1. McKinnon sustained a calf injury in practice earlier this week and Breida injured his shoulder in last week's game against the Cowboys.

To make up for the losses, the 49ers went out and signed free agent running back Alfred Morris, with whom Coach Shanahan is very familiar. Morris had his best years as a pro with the Washington Redskins, when Shanahan was his Offensive Coordinator. He now joins a backfield made up of 2017 fourth-round pick Joe Williams, Raheem Mostert, and Jeremy McNichols, who are likely battling for a maximum of two roster spots.

On the offensive line, both Jonathan Cooper and Joshua Garnett missed time due to knee injuries. Those injuries gave Mike Person reps with the starters, and he now has a legitimate chance at the starting job. Garnett reportedly received first team reps in practice this week and could potentially start tonight against the Texans. Right guard continues to be a battle worth watching, as both GM John Lynch and Coach Shanahan point to it as being the position facing the stiffest competition.

At wide receiver, Trent Taylor has missed some time with a back injury and has allowed players like Dante Pettis and Richie James more time to shine. James caught the game-winning touchdown last week against the Cowboys and Pettis hauled in a 53-yard reception during the game. Both rookies have stood out in camp practices as well. Taylor should make his return to game action tonight against the Texans, but he faces stiff competition for playing time with the emergence of both James and Pettis.

On the defensive side of the ball, the injury bug has hit both linebackers Malcolm Smith and Fred Warner. Brock Coyle has also been limited due to offseason surgery on his shoulder.

Elijah Lee has been a benefactor by the injuries as he received early playing time against the Cowboys. Lee could be a dark horse candidate to make the 53-man roster, as he provides versatility at linebacker and special teams value.

Tonight's game against the Texans could provide some interesting storylines to keep an eye on. Joshua Garnett will see his first game action since last season, Alfred Morris makes his 49er debut, and Coach Shanahan believes that quarterback is the only position where there are no roster spots up for grabs.

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