"I have to talk to Coach for exactly where they see me, but I'm pretty sure if I compare it, my size and abilities to Malcolm Smith -- that's probably where they are imagining me playing at," Jenkins told reporters in a conference call, according to the San Jose Mercury News.
Jenkins, 25, is at his best when using his sideline-to-sideline speed to make plays. But he is a bit undersized and that has often led to injuries.
He struggled with durability issues and missed 10 games the past two seasons for the Miami Dolphins because of various ailments. He finished with just 29 tackles in nine games last season.
The Dolphins selected Jenkins in the fourth round of the 2013 draft. He had his best season in 2014, his first year as a starter, when he led Miami with 110 tackles in addition to 3.5 sacks.
Manuel, 27, is expected to compete with second-year quarterback Connor Cook for the backup spot behind Raiders starter Derek Carr, who will be coming back from a broken right fibula suffered in Week 16.
Manuel will be reunited with Todd Downing in Oakland. Downing, the Raiders' offensive coordinator, was the Bills' quarterbacks coach in 2014.
"I used to even call or text Todd during the season the past two years and ask him what he was doing as far as teaching Derek," Manuel said on the conference call. "What was he doing to help his game jump levels so quickly? I felt like he elevated his game so fast for a young guy."
Manuel's arrival likely means the end of Matt McGloin's time in Oakland after four seasons. McGloin started seven games for the Raiders, including last year's regular-season finale at Denver, and went 1-6.
Cook, a fourth-round pick last spring who had not dressed for a game until the season finale, started the Raiders' playoff loss at Houston.
The Raiders also announced the re-signing of long-snapper Jon Condo on Monday.
ESPN's James Walker contributed to this report.