Mathews is often injured, and when on the field he has not been as productive as hoped. He has 11 career fumbles, only two fewer than his 13 career touchdowns.
Mathews is clearly a superior talent to Battle, but at 6'0" and 220 pounds, he has not been a consistent presence between the tackles.
His fumbles, combined with his injury issues (eight games missed over the last three years) mean that there is a clear track record of inconsistency with Mathews.
The Chargers need a more stable presence in the backfield, and Battle is proving to be just that. He played in Week 2 in place of the injured Mathews, and subsequently rushed for 69 yards and two touchdowns on just 14 carries.
Battle is a bigger, sturdier back at 6'2" and 240 pounds, and is not going to be the type of injury risk that Mathews is.
San Diego has again shown faith in Battle in Week 4—early in the contest he has enjoyed eight carries to Mathews' four, and has rushed for 21 yards and a touchdown as opposed to Mathews' negative-two yards.
There is a rhythm to the Chargers offense with Battle on the field, a rhythm that is hardly ever seen with No. 24.
Mathews fantasy owners need to be panicking to the utmost degree.
It was OK not to worry as you patiently awaited his return from injury, but now he is in the lineup and is still not getting many reps. The Chargers are clearly looking for alternatives—safer alternatives—and that means a heavier workload for Battle.