With his football future in doubt so many times, the running back leaned heavily on his other love: music.
''I wouldn't want to live without it at all,'' he said. ''If you took away music it would be like: `Man what are we going to do now?' It's everything to me.''
Grimes earned a degree in music at William & Mary while becoming the school's career rushing leader with 4,541 yards. He's been playing the piano since he was 7 years old, when his father told him he had to learn it if he wanted to keep playing football.
He's kept at both since then, and an injury to Arian Foster moved Grimes to second on the depth chart behind Alfred Blue. Grimes was used mostly as a third-down back last season when he appeared in each game and finished with 39 carries for 153 yards.
He was released by the Texans twice and has also been cut by the Jets and Jaguars since his rookie season in 2012. Coach Bill O'Brien respects guys like Grimes, who don't let such setbacks stop them from achieving their goals.
''It's really kind of a microcosm of life, like how do you handle it? I've been cut, I've been fired,'' O'Brien said. ''OK, well I'm going to go move on to something else in my life, or no, I'm going to keep grinding and stay with this dream and keep trying to make a team ... and those are our type of guys in a lot of ways.''
Though it was difficult at the time, Grimes thinks his winding path to this roster was a benefit in the long run; it put a chip back on his shoulder. When asked if he considers himself a musician who plays football or a football player who plays music, Grimes said he's probably a little bit of both.
''But I definitely lean on music a lot more just for peace of mind,'' he said. ''It's relaxing. I enjoy it probably a lot more. Because there's just so many unlimited possibilities you can do with music. You can listen to it. You can make music. You can study music.''
He doesn't have much time to work on music during camp, but does write lyrics occasionally. However, there's never a day when he doesn't listen to music - everything from current stars J. Cole and Kendrick Lamar to old-school favorites Parliament-Funkadelic pulses through his speakers.
He can sing, but prefers not to, instead focusing on playing the piano, writing songs and producing tracks.
Though he uses his music as an escape from everyday life, his two worlds intersect in a significant way. Grimes and a friend from college are working on music with Foster, who is out indefinitely after groin surgery. Because Foster is injured he isn't made available to the media and probably wouldn't talk about this anyway, which left Grimes a little sheepish about divulging their plan.
''We're working on a music project with Arian and I don't know if I'm supposed to say that, but something is coming,'' Grimes said.
The collaboration began when Grimes was with the Texans as a rookie in 2012 and discovered Foster had a piano in a random visit to his home. Now they work on music all the time and Grimes has helped him improve his piano playing.
''I showed him some stuff and he's picking it up,'' Grimes said. ''I didn't teach him everything, but I taught him mostly everything that was on the keys.''
He wouldn't share many details about the project, but did say they already have songs and are waiting for the right time to put something out. The 25-year-old Grimes did talk about the vibe of the music the two runners are making.
''I think it's kind of like a new-school feel with a good message,'' he said. ''It's not real basic. A lot of people just talk about stuff that they don't do really. But it's definitely influenced by a lot of old- school music because that's what we listen to, that's what we like. I think it's just a nice mix of new and old school.''
So could he at least describe one song they've made that he really likes? Grimes, who jokes about being nerdy and wore a hat with the words `No Swag' as he spoke, looked up and thought for a second before almost spilling the beans and abruptly changing his mind.
''There's one - uh ... we're just going to wait for the release,'' he said.
Grimes loves their sessions and believes it's necessary to have an outlet to escape from the daily grind of the gridiron.
''Sometimes we talk about football, but very rarely, because we're usually talking about music,'' Grimes said. ''Just to have your mind on something else sometimes is good. Because if it's just football, football all the time, you might drive yourself crazy.''
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