If this is the end of Randy Moss' career -- and it may very well be as the San Francisco 49ers wide receiver prepares to become an unrestricted free agent -- it's time to start wondering about his legacy. The Hall of Fame will be a certainty. The debate about whether he will be selected on his first ballot will be riveting. But what also shouldn't be forgotten is how much disappointment Moss created during his playing days. No player with his talent in NFL history ever left us wanting more.

It's hard to know whether Moss will retire for good this offseason because a CBSSports.com report said he still wants to play for a contender. What is clear is the 49ers have no interest in keeping him on their roster. The 36-year-old Moss tweeted farewell to his team over the weekend, saying he wished "we could've finished the job." It was an ironic choice of words because the same could be said about Moss' career.

There has never been a more gifted wide receiver in league history than Moss. He has size, speed, leaping ability and a killer instinct when he has been properly focused. At his best, Moss should've been the greatest receiver to ever catch passes in the NFL. Even he considered himself to be just that when the 49ers were preparing to play Baltimore in the days leading up to Super Bowl XLVII.

Randy Moss had 28 catches and three TDs in 2012 with the Niners. Ralph Freso/Getty Images

As baffling as it is to take issue with a six-time Pro Bowler whose career has included 982 receptions, 15,292 yards and 156 touchdowns, that's exactly what's happening here. Moss should've been in position to challenge every major receiving record Jerry Rice owned. Moss should've dominated the game for his entire career instead of having long lapses that left even his biggest fans shaking their heads. He also could've been more clutch, which is a part of his game that often goes unnoticed.

Moss has rarely played big in the biggest of moments. He's appeared in 15 playoff games during his career and only three times has he surpassed the 100-yard mark. Minnesota Vikings fans surely remember the touchdown pass he dropped in an NFC Championship Game loss to Atlanta during the 1998 season. Moss also managed only seven receptions total in his two Super Bowl appearances. We don't have to go into how Rice performed in these high-pressure situations. He came up huge when every opponent knew he was the man to contain.

This past Super Bowl was yet another example of how disappointing Moss could be at times. After spending media day hyping his career, he managed just two receptions for 41 yards in that loss to Baltimore. It could be argued that Moss even gave up on a pattern that resulted in a Colin Kaepernick interception in the first half. At a time when Moss could've elevated his game -- he caught 28 passes while mainly playing as a backup last season -- he reminded us once again why he can be so irritating in the first place.

It's not as if Moss hasn't had the intangibles. His teammates have raved about his work ethic regardless of where he's played. His coaches have been awed by his knowledge of the game. But the reality is that Moss always has been a front-runner. Put him on a talented team with a strong head coach and a shot at a championship, and he's likely to play out of this world. Stick him anywhere else, and it's only a matter of time before his frustrations fester and his willingness to quit emerges.

That's the only way to explain Moss' two years with the Oakland Raiders. He got stuck with a dysfunctional organization and lousy coaching and he immediately allowed himself to become part of the problem. The easy excuse for Moss in those days was that he was mired in a no-win situation. The real truth is that he let his game slide because he didn't have the desire to do anything else.

Moss' time with the Titans was forgettable and unproductive. Dilip Vishwanat/Getty Images

Moss slipped into a similar funk in 2010, when the New England Patriots traded him to Minnesota, the Vikings waived him after a month and the Tennessee Titans, who picked him off waivers, decided to not use him for the remainder of the year. It wasn't that his talents had eroded completely (although Moss eventually retired in 2011 after failing to find a suitable offer from any team). It's just that all the negative stuff in his career caught up to him that year. Even when he was doing positive things behind the scenes -- former Titans head coach Jeff Fisher, now with the Rams, said Moss mentored some younger receivers in Tennessee -- it seemed Moss was paying a heavy price for how people had perceived him earlier in his career.

That perception shouldn't change now that his playing days are winding down. As spectacular as Moss was during his first stint in Minnesota and his early years in New England, those highlights tend to blind people from the harder truths of his career. As former New Orleans Saints wide receiver Joe Horn once said, Moss made a living by going deep and taking the top off defenses around the league. When it came to going over the middle, blocking or doing some of the dirty work that also comes with the position, he was never too eager to make his mark in those departments.

It is fair to assume most people won't even think about those issues when they sum up Moss' career. They'll see all those deep balls, leaping grabs and gaudy statistics and remember him at his best. It's a predictable way of immortalizing a superstar. Seldom do people take the time to seriously critique everything about a star's playing days, especially when it involves somebody as dazzling as Moss.

That wouldn't be the best approach in this case. Jerry Rice accomplished more than any receiver in NFL history because he was hungrier than anybody else who played the position. Moss, on the other hand, had a comparable desire only when he felt disrespected or sensed a shot at a championship. In the end, both men will be remembered for their greatness. It's just too bad we'll never know how far Moss' talents actually could've taken him.