Alex Collins already on a short leash after first start with Ravens

Alex Collins carried nine times for 82 yards but also fumbled once. Evan Habeeb/USA TODAY Sports

BALTIMORE -- The Baltimore Ravens know Alex Collins is their best playmaking running back. The Ravens just don't know whether they can trust him.

In his first start for Baltimore, Collins produced the team's biggest plays, breaking runs of 50 and 23 yards. What's keeping Collins from securing the featured back role is ball security.

Collins fumbled for the second time in three games, which led to coach Johh Harbaugh putting him on notice.

"He won’t get any more opportunities [if he continues] -- the leash isn’t going to be long on that," Harbaugh said. "When you come in here and drop the ball however many times he has dropped, I’m not going to tolerate it. I like him. He’s a good kid, and he makes plays, but he has to hold onto the football."

In taking over for Terrance West, Collins totaled 82 yards on nine carries. That tied for the fourth-highest rushing yards in a game by a Baltimore running back since the start of the 2015 season.

But holding onto the ball has been a weakness for Collins. In three seasons at Arkansas, he fumbled 17 times and lost the ball nine times. He fumbled twice as a rookie last year with Seattle.

Now, Collins has coughed up the ball twice on 25 carries with Baltimore. His latest turnover proved costly. Collins' fumble in the second quarter came in Ravens territory and led to a touchdown that put Pittsburgh ahead 13-0.

Whatever spark Collins gave to the offense, he felt his turnover was a momentum changer.

"I feel like I let my teammates down," Collins said. "I put this one on me. I will definitely make up for it."

Collins joined the Ravens' practice squad before the start of the regular season after getting cut by the Seahawks. He impressed team officials immediately in his first two games with his physical running style, and he got the start Sunday against Pittsburgh because of his big-play potential.

After his fumble, Collins didn't get another carry for 14 minutes. On his first attempt since the turnover, he powered his way to a 50-yard run.

Collins' rise up the depth chart led to West's fall. West totaled minus-7 yards on four carries Sunday; he remained Baltimore's red-zone back, but he was stopped short on a key two-point conversion.

The Ravens' decision to start Collins didn't surprise West.

"[Collins] is getting it going," West said. "He had some long runs. Whatever the decision, it is what it is."

Asked if he was surprised by his second-fewest attempts as a Raven, West said, "No, whatever the play call is, I just accept it and go on. I’m just trying to win."

Collins' ability to generate yards is what separates him from West and Buck Allen. His average of 5.1 yards after first contact on Sunday ranked behind only LeGarrette Blount this weekend.

Collins is already leading the Ravens in rushing with 206 yards.

Does Collins expect to start Sunday at Oakland?

"I don't know what the coaching plan is," Collins said. "But I will always be ready."