TAMPA — Clyde Christensen said he knew it was a possibility, but news of Andrew’s Luck’s retirement still shocked the former Colts quarterbacks coach."I stay in touch with him and kind of knew that he was contemplating it,'' said Christensen, now the Bucs’ quarterback coach. "But I learned like everybody. I was watching the Florida-Miami game and it came across the bottom. All of a sudden, I had 15 texts in 30 seconds."Like everyone, the reality of it was shocking. It was a blow. It knocked the wind out of me.’’ MORE BUCS: Gabbert injury leaves Bucs scrambling for backup QB help Bruce Arians, the interim head coach of the Colts in 2012 when Luck was a rookie quarterback and led them to a 11-5 record and playoff berth, still was having trouble believing it."I know he’s been struggling with this latest injury but the last time I talked to him, he was still fired up about the year and the team,'' Arians said Sunday. "Knowing his toughness, and his mental toughness, this does surprise me. Something has got to be wrong somewhere because I know he loves the game so much. I (broadcast) two of his games last year (for CBS) and he was running off the bus to come say hi and tell me how the team was doing and the young receivers and how excited he was. To see it, that was very disheartening.''The fact is that 29-year-old quarterbacks who have made four Pro Bowls don’t walk away with three years remaining on their contract and leave about $70-million in earnings on the table.By most accounts, it’s the most surprising retirement since Michael Jordan left the NBA in 1993. Players such as Jim Brown, Barry Sanders and Calvin Johnson called it quits with plenty of gas in the tank before anyone would’ve expected. MORE LUCK: ‘He makes the decision of his life for his life’ What surprised both Arians and Christensen is that Luck is giving up football, a sport he enjoyed like very few others."I don’t know many people that love football more than him,'' Christensen said. "Everything about football. He loved the meetings. Every day he’d take his nap and I’d walk by the meeting room and wake him up. We put a little futon in there. He’s just such a fun guy to be around.“He got so much joy out of playing and the locker room and teammates and competing. Everything. He got a legit joy out of it, a childlike joy. To play football and not have that, obviously, he couldn’t live with that anymore.''And therein lies the biggest reason. Luck said it during his impromptu retirement speech following the Colts-Bears preseason game. He played through a shoulder injury in 2015 and 2016, then missed all of 2017 after undergoing surgery. Even though he led the Colts to a playoff appearance and earned a trip to the Pro Bowl last season, he struggled with a calf injury that lingered all off-season."I’ve been stuck in this process,'' Luck said Saturday. "I haven’t been able to live the life I want to live. Taken the joy out of the game, and after 2016, when I played in pain and was unable to regularly practice, I made a vow to myself that I would not go down that path again.''Arians, who has had his share of health problems that prompted him to leave the Arizona Cardinals after the 2017 season, can appreciate why Luck grew weary of trying to constantly recover from injury. MORE ARIANS: ‘If I die on game day, have a drink. Celebrate.’ “Oh, God. I love Andrew like a son,'' Arians said. "If you’ve battled injuries or sickness and you got healthy and boom you get it again ― people who beat cancer and they got it back, and they beat it again ― it wears on you. I mean, this isn’t as serious as cancer, but it is for him ― not knowing if he’ll ever throw again, not knowing if he’ll ever run again. The constant rehab and the separation from the team while you’re rehabbing, I think sometimes it’s really, really hard.''Christensen said because Luck felt an obligation to the Colts, his teammates and the city of Indianapolis, he didn’t want to let them down by being less on the field than he had been."He loved football more than money,'' Christensen said. "He carries it heavy if he thinks he’s letting his teammates down. I think that’s a hard one to live with. Those guys are perfectionists and they know what they can do and they can’t there.“I think he feels like I’m a distraction, I’m letting the team down. I don’t deserve the focus. I’m not playing.''Christensen said during the off-season he received an email from Luck from the Czech Republic. Luck had just gotten married and was excited about the upcoming season. Then came more complications from his calf injury. Christensen started hearing rumors that he was considering walking away from the NFL.Still, he didn’t believe it until the news broke Saturday night.“I think he’s one of the best to play,'' Christensen said. "He had everything. His rookie year, they emptied the roster and he just willed the thing. We had seven rookie starters and B.A. was there. He willed that thing to 11 wins and if you just watched him do it, he was spectacular. I think he’s one of the more accurate guys in the league. He’s one of the tougher guys. He’s brilliant. He’s got a photographic memory and he’s got off the chart people skills. You won’t find a player who doesn’t love being his teammate.''What will become of Luck now? Could he change his mind? Would he consider working again in football?“I don’t know,'' Christensen said. "He could disappear in the Swiss Alps and live in a cabin or he could be the President or the Commissioner of the NFL or anything in between. He’ll be interesting that way.“I think it’s a blow to football. We need the Andrew Lucks. We need the stars with humility. That’s a blow to the league. That’s a blow to the quarterback fraternity that he was really good for. Not to mention a blow to Indy. But it’s bigger than that.''