"There are 15 reasons why it's better," Richardson said Tuesday, per the New York Post's Brian Costello.
Marshall wore the No. 15 in his two years with the Jets.
After the Jets released Marshall in March, the 33-year-old signed a two-year contract with the New York Giants. The Giants are the fifth team Marshall will have played for since entering the NFL in 2006.
"There's a difference between playing next to somebody and playing for them," Forte said. "We were at practice [last year] and I was like, 'Guys, everybody is out here as an individual and we're just playing next to the guy. Do you really know that guy?'"
Marshall had a unique way to describe the feeling around the team during an appearance on Showtime's Inside the NFL in January (h/t the Associated Press' Dennis Waszak Jr.).
"The best way I can describe it is, having a diaper on and never changing it," he said. "And just sitting in that diaper the whole year. That's how our year was. It was a bad year."
The internal problems that plagued the Jets help explain why the team went from barely missing the playoffs in the final week of the 2015 season to going 5-11 a year ago.
Based on Richardson's comments, Marshall's departure could be a case of addition by subtraction.
At the same time, Marshall finished first on the team in receptions (59) and second in receiving yards (788). Aside from a few mid-round selections in the 2017 draft, the Jets haven't done much to fill the void he left in the passing game.