The biggest key to success in fantasy football is understanding a player's true fantasy value, and while every fantasy point earned is worth the same, those owners who can accurately predict future value are those who will be the most likely to succeed.
One player who seems to be quite the enigma this season is Mike Tolbert. Currently, Tolbert sits tied for eighth for fantasy points scored by running backs, so on the surface you might think his job is 100 percent safe. You should not share in that opinion. A closer look at Tolbert's production reveals that about two-thirds of his fantasy production has been as a receiver and that Tolbert has been a failure as a rusher so far early this season.
What this means is that Sunday's game against the Kansas City Chiefs is key for Tolbert owners. If Tolbert does not show basic competence running the football, you should bail immediately. Consider this: Through two games, the New England Patriots are allowing 4.5 yards per carry and the Minnesota Vikings are allowing 4.0. In his games against those teams, Tolbert managed 1.1 and 2.9 yards per carry, respectively. The Chiefs are actually stingier than both of Tolbert's previous opponents, coming in at 3.7 yards allowed per carry.
Looking at those numbers, it's clear that Tolbert is not performing as a rusher, but there's already reason to worry about his involvement in the passing game. From 2006 through 2010, these are the average number of targets Chargers running backs received per game: 2006, 6.8; 2007, 7.5; 2008, 8.7; 2009, 7.9; 2010, 9.8. While that number has been trending up, we are seeing a gradual increase in the involvement of the running backs in the passing game. Through two games this season, that average is 18.0 targets per game. That means the amount of time Philip Rivers is passing the ball to his running backs has increased by over 80 percent compared to last season. When you consider last season marked the highest involvement by Chargers running backs in the passing game for the previous five seasons, it should be apparent that the 2011 level of involvement will extremely likely be reduced going forward.
The other factor in Tolbert's value is the performance of 2010 fantasy bust Ryan Mathews. Through two games, Mathews is averaging 4.5 yards per carry and has been targeted 14 times. While most people aren't accepting this as a 50/50 time-share at this point, that is exactly what it's become. If Mathews continues to be the more productive runner, he's going to find himself on the field more often, which means fewer snaps for Tolbert.
Most Targets, Week 2
Receiving yardage is variable because so much of it is dependent on where the quarterback elects to throw the ball. The variations in the number of times a player is targeted by his quarterback may greatly alter a player's value. It's important to look at the underlying target metric on a weekly basis to determine which stud performances were flukes and which dud performances can be written off to a bad day.
On the right, you'll see all the players who received seven or more targets in Week 2, but here are some of the top storylines from Week 2.
Vincent Jackson, San Diego Chargers (15 targets, 10 receptions, 172 yards): After being almost invisible in the Chargers' Week 1 win, Jackson lived up to the expectations the fantasy community had for him entering this season. The bigger item to draw from Jackson's dominance against the New England Patriots is that the Patriots haven't shown to have an answer for larger wide receivers early this year. While Steve Johnson will be a trendy pick next week, look instead for David Nelson (13 targets for 10 receptions and 83 yards), who is 6-foot-5, to be the more productive receiver Sunday.
Jeremy Maclin, Philadelphia Eagles (15 targets, 13 receptions, 171 yards): Rarely does a receiver dominate an NFL game the way Maclin did yet get remembered for one of the two passes that he failed to haul in, but that summarizes Maclin's Sunday night. Even if Michael Vick is kept out of Sunday's game, Maclin should shine. He looks to be 100 percent recovered from his offseason illness.
Matt Forte, Chicago Bears (14 targets, 10 receptions, 117 yards): In point-per-reception leagues, Forte is going to finish near the top of the running back rankings. Through two weeks, he has been targeted an amazing 15 times. Those 7.5 targets per game are greater than the average that Marshall Faulk had in 2001 as a member of the St. Louis Rams' "Greatest Show on Turf." Look for that large number of targets to continue, as other Bears wide receivers aren't stepping up (Devin Hester, one reception on nine targets).
Mike Thomas, Jacksonville Jaguars (11 targets, 3 receptions, 29 yards): Someone has to be the No. 1 receiver for the Jaguars, and it'll be Thomas for at least as long as Marcedes Lewis remains sidelined. However, the change of starting quarterbacks to Blaine Gabbert will severely affect Thomas' fantasy value. Because of the switch, Thomas needs to find the way to your fantasy squad's bench until the rookie quarterback proves he can be a viable signal-caller in the NFL.
Nate Burleson, Detroit Lions (9 targets, 7 receptions, 93 yards): Burleson has publicly stated that he views himself as the Wes Welker of the Lions' offense. If he's going to provide significant fantasy value, he'll need to put up Welker-esque numbers. While he's done that in the first two games, the emergence of Titus Young (7 targets, 5 receptions, 89 yards) will severely hamper that possibility. Burleson makes a decent start for the next two or three weeks, but eventually it'll be Young as the second option in the Lions' passing attack.
Eric Decker, Denver Broncos (9 targets, 5 receptions, 113 yards): I called Decker as my deep sleeper in our final round of sleepers and busts. I'm not backing down now. Decker has all the skills necessary to be a very good receiver and Brandon Lloyd's injury gave him the opportunity he needed. I'm all-in on Decker.
Dallas Clark, Indianapolis Colts (8 targets, 4 receptions, 32 yards): Kerry Collins is at his best when he's not trying to go down the field, so a logical evaluation would be that Clark should be the Colts receiver whose value changes the least from Manning to Collins. However, Collins has been erratic, as evidenced by his 50.7 completion percentage, which is killing Colts drives. Until Collins shows he can be a serviceable option for the Colts passing attack, Clark is nothing more than a borderline starter in most fantasy leagues.
Denarius Moore, Oakland Raiders (8 targets, 5 receptions, 146 yards): I'd say that Darrius Heyward-Bey might have just Wally Pipped himself, but that would imply that Heyward-Bey had lived up to any of the hype that surrounded him when the Raiders drafted him. Moore looked like an absolute beast Sunday. Moore is going to be the Raiders' No. 1 wide receiver for the rest of the season and should be owned in all formats.
Danario Alexander, St. Louis Rams (7 targets, 3 receptions, 122 yards): Alexander gets the great publicity of a solid game against the New York Giants on Monday night, but don't raise his value too quickly. Rookie Greg Salas (8 targets, 4 receptions, 27 yards) was given opportunities, too. Eventually both Danny Amendola and Mark Clayton will return for the Rams, which is likely to push both out of the starting lineup.
Big plays and up close
The amazing part of Jones-Drew's five carries of 10 or more yards is that all of those runs were attained against defensive fronts with either five or six defenders on the line of scrimmage. Those fronts are designed to stop the run and Jones-Drew executed in a big way.
Left for dead at the end of the preseason, Thomas stepped up in a big way against the Houston Texans. He looked good enough that the Miami Dolphins cut veteran Larry Johnson. Expect Thomas to become the workhorse back for the Dolphins as the season progresses.
• After a Week 1 that featured just two players with four or more carries inside their opponent's 10-yard line, Week 2 featured nine players who had four or more such carries: Rashard Mendenhall (6), Cam Newton (5), Adrian Peterson (5), Michael Turner (5), Arian Foster (4), Peyton Hillis (4), Fred Jackson (4), LeSean McCoy (4) and Keiland Williams (4). Additionally, Jahvid Best, Shonn Greene, Mark Ingram and Mike Tolbert each had three of carries in that scoring zone.
Of those 13 players, only Arian Foster, Mark Ingram and Mike Tolbert failed to score.
In case you haven't been paying attention, Williams is a member of the Detroit Lions, which means Best's owners should keep a close eye on Williams' work in this area of the field. When Mikel Leshoure went down to injury in the preseason, the prospect of Best getting regular goal-line work increased. If Williams becomes a bit more proficient in this area, Best's current value could take a significant hit. Keep an eye closely on this metric if you own Best.
Jackson may have had four carries, but three of them went for either no yards or negative yards. Fortunately for his owners, the Buffalo Bills don't appear to have a better goal-line option at this moment, so there's not much to worry about, but monitor any news of the Bills working out additional running backs.
Ken Daube is a fantasy football analyst for ESPN.com. For game-day insights, follow him on Twitter @KenDaubeESPNFF.