FOXBOROUGH, Mass. — Tom Brady spent his first day in suspension exile on Saturday. He began his 30-day journey away from Gillette Stadium, away from the NFL.

For Brady, having no contact with the team during the next month, per league guidelines, will be a challenge. And then some.

Just ask Rodney Harrison. The former Patriots safety served a four-game suspension in 2007.

“It’s going to be the longest month of his life. It’s going to absolutely drive him crazy,” Harrison said. “It’s going to seem like 24 hours is 48 hours. It’s going to feel like every hour is three hours. You get very bored.”

Harrison’s suspension stemmed from his admission to federal investigators he knowingly obtained and used HGH. Brady, of course, received his penalty over the NFL supposition that he was generally aware of footballs being illegally deflated prior to the 2014 AFC championship game against the Colts.

Harrison knows firsthand what Brady puts into the daily and weekly routine of preparing to play each Sunday. He watched and observed Brady when he was a teammate. Harrison was similarly maniacal about preparation.

“I know Tom is a big student of the game. He likes preparation. He likes routine. It completely changes when you don’t have the football,” Harrison said. “Yes, you can go to the mall and do things with your family and kids, whatever, but it’s just not the same. I’m telling you, it’s going to be the longest month of his life.”

Patriots defensive end Rob Ninkovich also is suspended for the first four games of the season for using performance-enhancing drugs.

Brady wouldn’t reveal any of his training plans for the league-imposed sabbatical. Asked about it last Tuesday, he cracked: “I don’t want to give away all of my tips.”

Harrison didn’t mind sharing what he did to fight the boredom and try to stay in the game. For one, he hired a training buddy. While Brady might enlist the help of former teammates to catch passes, which has been suggested in a number of circles, Harrison paid someone to work out with him.

“As far as what I did, I actually hired me a guy. We went out on the field, and I was in full uniform working out,” Harrison said. “I’d lift weights, I’d put my uniform on, I would do sprints, all types of defensive back drills. I’d mimic tackling with dummies, so I’d do a lot of football related stuff in an open field with my pads on.

“No one saw me. But that’s what I did, and I did it faithfully every day. I took a couple days off. But it kept me sharp. Is it perfect? No, it’s not perfect. You’re not going to have the timing, the speed with all the other players flying around you, but that’s just something I did that kept me in tune.”

Brady can’t have any contact with “club personnel, no exchange of playbooks/game plans or sending video on tablets or other electronic devices.” He also cannot “engage in any team football-related activities or discussions with teammates, even if away from the club facility.”

Harrison wasn’t aware of all that. So it’s only more boredom and crazy time for Brady, although Harrison noted one positive: the rare idle time allows for a period of self-reflection.

“That moment really gave me an appreciation. Outside of being injured, that moment gave me an opportunity to appreciate everything I’d accomplished and everything I had in my life. It’s a good moment for reflection, but it also gives you a burning desire,” Harrison said. “People think I cheated. People think I can’t do this without whatever, and all of these different things go on inside your head. That’s the worse thing the league could have done, is piss Tom off, and give him time off and say that he cheated.”

We got an inkling of an angry Brady last year before injuries took their toll on the offense. But now that he’s officially banished from the facility and practice fields until the day after the team’s Oct. 2 game against Buffalo, we can only imagine what the Revenge Tour will be like this time when it begins Week 5 in Cleveland.

Said Harrison: “I’m excited (to see how it plays out), but once again, it’s all part of it. It’s something you don’t want to see anyone go through, but at the same time, it’s not the end of the world. It’s four less games for him to be out there for injury purposes. If anybody can sit four games and come back and have a stellar year, it’s Tom.”

So after being driven crazy for the first month, Brady is going to come back crazy good the rest of the way. That’s Harrison’s prediction.

And knowing Brady, it’s hard to bet against.

PRACTICE SQUAD: Running back Bishop Sankey, a second-round pick by the Tennessee Titans in 2014, was one of eight players added Sunday to New England’s practice squad, according to the Providence Journal.

Sankey rushed for 569 yards and caught 18 passes as a rookie, but his numbers declined in 2015 to 193 yards rushing and 14 receptions.

The practice squad also includes defensive ends Geneo Grissom and Rufus Johnson, defensive tackle Woodrow Hamilton, wide receivers Devin Lucien and Devin Street and offensive linemen Clay DeBord and Chris Barker. All except Street and DeBord were with the Patriots during training camp. Street played two seasons for the Cowboys, and DeBord is a rookie free agent who was released by the Cardinals.