Cassius Lee Marsh (born July 7, 1992) is an American football defensive end for the San Francisco 49ers of the National Football League (NFL). He was drafted by the Seattle Seahawks in the fourth round of the 2014 NFL Draft.  He played college football at UCLA. He has also played for the New England Patriots.
Marsh attended Oaks Christian School in Westlake Village, California.  He was a member of PrepStar Dream Team and Tacoma News-Tribune Western 100.  He was ranked as 22nd defensive tackle prospect nationally by Tom Lemming/MaxPreps during high school.  He was selected to the GoldenStatePreps.com All-State first team and All-SoCal first team.  He was named CIF-SS All-Northwest Division co-Defensive Player of the Year in his junior season.  He played in the U.S. Army All-America Game after high school.  He recorded 83 tackles, 23 sacks, in his senior season at high school. 
Rivals rated Marsh as a 4-star prospect being the No. 4 defensive tackle, No. 6 prospect in the state of California, and the No. 33 prospect overall regardless of position. ESPN recruiting rated Marsh as a 3-star prospect being the No. 33 defensive tackle, and the No. 33 prospect in the state of California. 247 rated Cassius as a 4 star prospect being the No. 11 defensive tackle, and the No. 142 overall prospect (No. 114 composite ranking) regardless of position. SCOUT rated Cassius as a 4 star prospect as well. Many major college programs offered Marsh and it ended up coming down to UCLA and LSU. Ultimately, Marsh chose UCLA. However, Marsh had initially committed to LSU before, so Marsh actually flipped his commitment on LSU to go to UCLA in January 2010. Marsh's main reasoning for the change of heart was that by going to UCLA he would be able to be closer to home.
In December 2010, he was selected to the Rivals.com Pac-10 All-Freshman team in his freshman season.   He was winner of UCLA's John Boncheff, Jr. Memorial Award for Rookie of the Year in his Freshman season.  
Marsh was drafted by the Seattle Seahawks in the fourth round, 108th overall, in the 2014 NFL Draft.  He was signed to a four-year contract on May 19, 2014.  Marsh recorded first sack and first forced fumble of his NFL career against the Miami Dolphins in the season opener on September 11, 2016.
New England Patriots
San Francisco 49ers
Marsh is the son of Curtis Marsh Sr. and the half-brother of Curtis Marsh Jr.. Curtis Sr. was a wide receiver who played college football at Utah and was then drafted in the 7th round in the NFL draft in 1995 by the Jacksonville Jaguars. Curtis Sr. played three seasons in the NFL for the Jaguars (2 seasons) and the Pittsburgh Steelers (1 season) before going to Canada to play in the CFL where his career flourished and he even became a CFL All-Star in 2000. Curtis Jr. played college football at Utah State initially starting off as running back (for two seasons in 2007 and 2008) before a position change to play defensive back (for two seasons in 2009 and 2010). Curtis Jr. was a 3rd round draft pick in the 2011 NFL Draft by the Philadelphia Eagles.