SAN DIEGO -- Keenan Allen knows he's not sneaking up on anyone this season.

As a rookie selected in the third round of the 2013 draft by the San Diego Chargers, last season was supposed to be a developmental year for the Cal product. But season-ending injuries to Danario Alexander and Malcom Floyd thrust Allen into the starting lineup.

Allen responded by finishing with 71 receptions for 1,046 yards and eight touchdowns, developing into the go-to receiver on the perimeter for Chargers quarterback Philip Rivers.

Because of that effort, Allen debuts at No. 75 on this year's ESPN's #NFLRank list.

"I just want to build off of last year, help my team as much as I can out there and try and lead us," said Allen, when asked about what he'd like to accomplish in his second season.

Rivers said Allen's ability to understand the entire offense and his role in it helps the big receiver play fast. Along with that, at 6-foot-2 and 211 pounds, Allen has the short-area quickness to consistently create separation.

"What he does that makes him so good is he's very creative with his releases and his moves at the top of his routes, and yet he's very subtle," Rivers said.

Allen was targeted 107 times in 2013, the second-most behind tight end Antonio Gates (113) on San Diego's roster. In 2014, expect Allen to receive a similar amount of looks.

He'll have the added benefit of having Floyd back on the field. At 6-5 and 235 pounds, defenses will have to account for Floyd on the perimeter, along with Gates in the middle of the field.

"It's great," said Allen, when asked about having Floyd back. "It's going to take a lot of pressure off of me, along with Antonio Gates. I had a great year last year, so I'm guessing I'm going to get a lot of attention. But with Malcom out there, they're not going to really be able to double me up."

Further, NFL receivers often experience their biggest growth in development between their first and second seasons. Allen said he's worked on his speed and added a few pounds to build on what he accomplished as a rookie.

"I really attacked my speed," Allen said. "I'm just trying to get quicker off the ball and be that deep threat."