Both are versatile members of the secondary, both are two-year starters and are senior captains. Thanks to their strong play, the Tigers defense has not allowed a touchdown in the last seven quarters heading into Saturday's game at Vanderbilt (2-4, 0-3 SEC).
The paths that led them to Missouri (4-3, 1-3) are not so alike.
Dennis spent two years at Hinds Community College in Raymond, Miss., after getting no Division I scholarship offers out of Leland, Miss., High in 2012.
''It was pretty difficult at first,'' Dennis said. ''But as a player, you've just got to keep pushing. You don't always get it how you want it, so you've just got to keep fighting for whatever you want.''
Dennis totaled 65 tackles, three interceptions and two fumble recoveries at Hinds, earning NJCAA All-American status and several D-I scholarship offers. He chose Missouri over Arkansas and Auburn, among others, citing academics as a deciding factor.
''I knew I was going to go somewhere and eventually graduate,'' said Dennis, who majors in sports management. ''I immediately looked at the graduation rate for Missouri and it was pretty high. My family thought that was very appealing.''
Two former Tigers, safety Kenji Jackson and tight end Eric Waters, are from Mansfield. Jackson started 35 games from 2008-11 and was also a captain, serving as a source of inspiration.
''That's someone I've always aspired to be like,'' Simon said of Jackson. ''He's such a hard worker, and he was very successful here. I've always wanted to kind of mimic his success.''
Dennis is also inspired by a former teammate.
Strong safety Braylon Webb had 259 tackles and seven interceptions for Missouri from 2011 to 2014, setting an example in Dennis' first year.
''The way he carried himself ... he was real quiet,'' Dennis said. ''He didn't get in a lot of trouble. Guys respected him. He had a great personality. Coaches respected him. That's the type of guy I kind of want to be around here.''
Dennis and Simon help anchor the Tigers' defense, which allows a stingy 165.3 passing yards per game, ranked first in the Southeastern Conference.
Dennis has 24 tackles, including two for loss, with a sack and interception.
First-year defensive coordinator Barry Odom is pleased with Dennis' acclamation to his scheme. Odom credited cornerbacks coach Cornell Ford for Dennis' development.
''Junior college guys, their window is pretty short,'' Odom said. ''Coach Ford's done a great job of bringing him along and getting him in the position that he is today.''
Simon has a career-best two interceptions, a fumble recovery and three pass breakups. Simon is far from satisfied, saying he and Dennis need to ''do more.''
''Just be as productive as we can,'' Simon said. ''The more productive we are on the back end, the easier it's going to make everything for the guys up front.''