They just can't.
The oft-injured, handsomely paid and somewhat gadgety wide receiver played only 20 snaps during the regular season and 19 snaps in one playoff outing in 2013, according to Pro Football Focus (subscription required).
Although the Seahawks likely had major plans for Harvin this season—as evidenced by the six-year contract Seattle gave him in March with $25.5 million guaranteed—a serious, rather nagging hip injury and concussions have kept him off the field for basically the entire year.
After an insanely frustrating campaign in Seattle, it's hard to blame the Seahawks for trying to get their expensive toy involved from the get-go in the divisional round against the New Orleans Saints.
Russell Wilson's first two passes of the game went in Harvin's direction—a minus-one-yard catch and an incomplete pass, the latter being the play on which he may have suffered a concussion.
During the third possession, Harvin was given the ball on a jet sweep that went for nine yards.
On Seattle's fourth drive, which came early in the second quarter, Russell Wilson connected with Harvin on a six-yard pass before the relatively small receiver made a tremendous high-pointing grab on a 16-yard pick up.
Having recovered from the huge hit inflicted by safety Rafael Bush earlier in the game, it was clear Seattle wanted to utilize Harvin in a variety of ways, and it was also apparent how effective the yards-after-catch demon could be.
But a throw to Harvin in the corner of the end zone on an improvised play with under two minutes remaining in the first half led to another big hit, and the former first-round pick was unable to return.
In Minnesota, Harvin was used as a "horizontal player," meaning many of his targets came on screens.
For perspective on how low that is, the player above Harvin—Dexter McCluster of the Kansas City Chiefs—had an average depth of target of 5.5 yards.
For a guy who ran the 40-yard dash in 4.41 seconds at the 2009 combine, Harvin certainly has the vertical speed to threaten defenses deep, and because of his expensive price tag, the Seahawks likely wanted to tap into every last ounce of his offensive value as possible.
But the downfield shots put Harvin at risk, as witnessed during the last time he was on the field. He simply can't take any more monstrous blows from safeties sprinting over from center field like a missile.
In Super Bowl XLVIII, getting Harvin the ball quickly and allowing him to see what's in front of him will be in the best interest of the Seahawks and Harvin himself.
He possesses tremendous vision, agility and burst. So, rather easily, Harvin could be used on jet sweeps and short, high-percentage passes. That was his specialty with the Vikings.
How many target should Percy Harvin get in the Super Bowl
Frankly, with the dearth of speed and quickness in Denver's secondary now that Chris Harris is injured—outside of Dominique Rodgers-Cromartie—Harvin may actually be most effective in the quick passing game.
Coincidentally, getting the ball out of Wilson's hands as fast as possible will be the most logical way to negate Denver's overachieving pass rush.
According to PFF, no quarterback in the NFL faced pressure on a higher percentage of his dropbacks than Wilson did during the regular season at 43.8 percent.
Unsurprisingly, Wilson has the highest pressure rate in the playoffs, too, at 53.7 percent.
Therefore, to keep Percy Harvin away from huge hits in the secondary and to slow down Denver's defensive front, the Seattle Seahawks should incorporate him as a situational, short-passing security blanket for Russell Wilson in Super Bowl XLVIII.