Borderline impossible, that is, for the sake of specificity.
Surveying the situation in Cleveland with any kind of depth will give any casual NFL observer a headache. A combination of factors have essentially set Rainey up for failure, even before he could be counted on as even a moderately productive player.
First of all, Willis McGahee will likely take over at No. 1 on the depth chart if he signs and passes a physical.
Rainey has looked decent as a kickoff returner, but shows nothing to indicate he's any sort of game-changer. The fact that he's never carried the ball in the NFL reflects just how ridiculously unproven the Browns' current backfield is.
This whole vertical-based passing game offensive coordinator Norv Turner has brought with him was supposed to cater to Brandon Weeden's strengths as a quarterback.
However, he can't very easily make a strong case for himself as the future franchise quarterback without any blocking. Check out this statistic from Pro Football Focus.
The constant harassment has caused Weeden to absorb an exorbitant amount of punishment, and totally halted the ability for last year's No. 3 overall pick Trent Richardson to get going.
Head coach Rob Chudzinski beat back a question in the trade press conference. When asked what the Browns would do at running back, he responded that the team had Rainey and Chris Ogbonnaya right now.
That's why this unexpected opportunity has presented itself for Rainey in the first place. The undrafted free agent spent last year with the Baltimore Ravens, where he went on injured reserve in November with a knee injury.
Rainey didn't even go through Browns training camp, so he's learning a completely new offense on the fly.
Yeah, good luck with that.
Due to the thumb injury to Weeden, he has gotten the proverbial thumb from the gridiron in favor of third-stringer Brian Hoyer, who will start Week 3's road game against the Minnesota Vikings.
This is the Hoyer who backed up Tom Brady for three seasons with the New England Patriots, but it's also the same Hoyer who threw nine touchdowns and nine interceptions and completed 51 percent of his passes as a senior at Michigan State.
Hoyer is the 19th starting quarterback the Browns have deployed since re-entering the NFL in 1999.
The Browns are scoring, um, eight points per game, and averaging a horrendous 275 total yards per contest to date.
The disappointing play of the offensive line's right side has been a big reason for the constant pressure on Weeden and the terrible blocking, which held Richardson back from putting together any consistency.
Guard Oniel Cousins has been an abject disaster, while 2012 second-round pick Mitchell Schwartz looks to have regressed. Or something.
Absent some sort of miracle by Hoyer, who is just as statuesque in the pocket as Weeden, Rainey's reign as starter shouldn't last beyond one game without a passable passing game to complement him.
The return of standout receiver Josh Gordon could help the cause, as could the Vikings' shaky defense. Then again, Hoyer was a third-stringer until the surprising anointment as starter over Jason Campbell, and Rainey is still trying to pick up the offense.
It's no knock on Rainey, but he is set up to average no better than the 3.5 yards per carry Richardson managed behind suspect blocking.