49ers rookie D-lineman Alfred Collins believes he’s only scratching surface

SANTA CLARA — Defensive linemen Mykel Williams and Alfred Collins came to the 49ers together.And through the first nine games as rookies, they were on the field a lot together, too.Williams and Collins rank first and third among 49ers defensive linemen in snaps played this season.Williams, the 49ers’ first-round draft pick, saw his season come to an end on Sunday with a torn anterior cruciate ligament in his right knee.Collins, the 49ers’ second-round draft pick, was devastated.“It hurt deeply,” Collins told NBC Sports Bay Area. “You hate to see that happen to your brother. He worked his butt off every day to be where he’s at right now. Now, it’s adding gasoline to the fire.“Every day we were intentional on things we needed to do to get better. We were climbing that ladder every day together.”Williams started each of the 49ers’ first nine games, and played more snaps (385) than any other defensive lineman on the team. Collins has yet to step into a starting role, but he played the role of the closer when the 49ers faced the Los Angeles Rams in Week 5.Collins made the defensive play of the year when he...