Hayes assumed the nagging pain and the bumps and bruises he'd accumulated in his first two seasons with the team were nothing more than soft tissue injuries, the types of things that would go away with some offseason rest and relaxation. He waited through the 2013 offseason and it never happened. So when this offseason began, he decided to get further inspection.
What Hayes and the doctors found wasn't pretty. So he went to coach Jeff Fisher, who told him to get it fixed. The result was Hayes spending most of January and February having surgeries. Yes, surgeries, plural.
Hayes started with collarbone and ankle operations before turning to a more serious issue, surgery on a hip that had been bothering him for his entire stay in St. Louis. The procedures kept Hayes out for all of the team's organized team activities and had him sitting in the early days of training camp.
Last week, Hayes began to get back in the mix for individual drills. On Thursday night, Hayes took a bigger step as he returned for a handful of team drills and some work in one-on-one pass rush drills.
"This offseason was more about getting myself healthy," Hayes said. "The past few years I have been playing pretty hurt. I wanted to be able to come in and really help my team this year so I wanted to maximize the chance to get my body back super healthy and I did good. The training staff did a great job. They did an excellent job. We just grinded it out. This is probably the best I've felt since my second season in the NFL."
For those keeping score at home, Hayes' second season was all the way back in 2009.
The Rams also did their part to help alleviate some of Hayes' workload. He's been a key contributor as the top backup at defensive end, especially on running downs, but had the added workload of coming in as an interior pass-rusher on third downs. The team's pursuit of free agent tackles Alex Carrington and the choice of Aaron Donald with the No. 13 overall pick were moves made in part to help ease Hayes' burden.
In his two seasons in St. Louis, Hayes has posted 63 tackles, 12 sacks, three fumble recoveries and an interception while playing just 685 snaps. He's become one of the best rotational defensive linemen in the league and is viewed as one of the emotional leaders in the locker room.
Simply having Hayes and offensive tackle Jake Long, who is recovering from knee surgery, back on the field is enough to bring a smile to Fisher's face.
"It was great to have William and Jake back," Fisher said Thursday night. "They've been working hard, we are just going to ease them back into it. No issues today so we'll get some more reps tomorrow but it's good to get them back. They're both excited."
Beyond getting the operations needed to come back healthy in 2014, Hayes was diligent about the offseason workouts he could do, trimming his weight from 286 pounds to what he estimates is between 275 and 278 pounds. He spent most of his offseason in St. Louis working with the team's training staff but also made sure to have trainers available for trips home to North Carolina and out to New York.
And though Hayes hasn't been able to practice, he has made a habit of getting extra reps when he can before and after workouts with right tackle Joe Barksdale there to assist.
The plan from here is to continue working Hayes in and getting him reps when possible. He's hoping to get some work in the preseason games, reps he says he wants to get so he doesn't feel like he's playing his way back into shape when the season starts.
"It did wonders for me after I got it (the surgery)," Hayes said. "I felt better the day after I got it than I did during the season. It's a process I'm going through right now. The hardest part is just being able to be patient, trying to beg for reps every day. It's a process."