NFL Network's Ian Rapoport reported Saturday that 49ers RB Christian McCaffrey was being placed on IR, knocking fantasy football's No. 1 pick out for at least four weeks. 

Jordan Mason, McCaffrey's backup, was added in 31 percent of CBS Leagues this past week and is now rostered in 97 percent of leagues. Mason carried the ball 28 times last week for 147 yards. 

While there isn't a ton of direct actionable advice here, there are some elements to consider in both the trade market and the waiver wire. 

First and foremost, trying to figure out the handcuff to Mason for the next four games is a bit of a fool's errand — the 49ers seem to be able to slot anyone on their roster in at RB and coax 100-plus yard games out of them. Deebo Samuel will most likely get 7-9 carries a game, and your best bet at the moment for a pure RB is Isaac Guerendo, who is 6% rostered and played 13 snaps (10 on special teams) in Week 1. You might as well grab him if you have Mason or someone like Jakobi Meyers is sitting at the end of your bench. 

For an inspired waiver wire choice in deeper leagues, consider former Bucs RB Ke'Shawn Vaughn, who is on the 49ers' practice squad and was at one point a chic fantasy sleeper. The 49ers do weird things like this — Raheem Mostert and Elijah Mitchell were nowhere near fantasy radars before their breakouts. Keep in mind, however, we're talking about IF Mason gets hurt, which would mean a run of historically bad RB luck for this team. 

A quick interlude from Paul Charchian, Head of Guillotine Leagues: 

Christian McCaffrey represents a buying opportunity for anyone who feels confident that they've fielded a playoff-bound roster. The team manager with CMC is probably in a tight spot, having burned 1.01 on a player who won't provide help until midseason. You could buy CMC now, at a historically low cost, then stash him until he's healthy, and (potentially) ride him into the fantasy playoffs.

McCaffrey's absence — which will be at least four weeks, and could be more, depending on the severity of his vague injury — opens up some targets in the pass game; Mason has four total receptions in his NFL career and may not be a perfect 1-for-1 replacement here. The logic would say to bump up George Kittle and Brandon Aiyuk. Samuel gains value both for picking up a couple more carries and possibly being sent out for shorter passes in McCaffrey's absence.  Maybe Jauan Jennings sees more snaps? Perhaps Kyle Juszczyk sees slightly more TD potential?

In the trade market, poking around for McCaffrey comes with massive risk — and huge upside. The frustration of another McCaffrey injury, though, might make him available for someone like Joe Mixon, if McCaffrey's GM is fatigued to the point of just wanting to get rid of him. James Cook (and something else) might get a deal done, as well. The 49ers' handling of their injuries and constant obfuscation helps you out if you want to go after McCaffrey, just know that there is a very real scenario where he's called out for the season and needs surgery — but also one where he's back in Week 6 and getting 180 total yards a game for the next three months. 

This is why our game is so much fun. 

Jordan Mason is the safe play — he'll hold value even with McCaffrey back in some 12-team formats. But get excited if you have Samuel or a string of other skill position players — the next 4-6 weeks should be even more fruitful than advertised.