"I've thought about it a little bit," Grimble answered, when asked if he'd come to a decision about his future. "It's more of a personal decision for me, I feel like with everything that's happened this season that I think it will be best for me to stay in school.
"So that's probably what I'm going to be doing this year."
The tight end caught 23 passes for 248 yards this season including two touchdowns in his 12 games played.
Grimble suffered multiple injuries throughout the year, including a nagging ankle injury as well as a shoulder injury.
He did not play in the Trojans' Nov. 1 win at Oregon State.
USC will play its final game of the season Dec. 21 in the Las Vegas Bowl against Fresno State.
Grimble says between now and the Jan. 15 underclassmen deadline to declare for the draft it is "very unlikely" he will change his mind and announce for the NFL.
"I'm going to wait it out, look at everything, just go through the process and get used to it," he explained. "But right now that's where I'm at."
If Grimble does indeed return for his fifth season of eligibility he will no doubt be a boost to new coach Steve Sarkisian's offense. At Washington, Sarkisian utilized tight end Austin Sefarian-Jenkins for 413 yards on 33 receptions, including seven touchdowns.
Sarkisian plans to implement his same offense at USC.
"Sark recruited me out of high school," Grimble explained. "[I] love what he did over there with Washington's tight end. He did a great job.
"I'm looking forward to seeing what he can bring to our offense and seeing how he can utilize us. It's going to be an exciting new year, so once the bowl game is over, we'll be ready to play for him."