Separating seasonal stat lines and/or Player Rater placement from going-forward rankings (and/or projections) can be a challenging task for fantasy baseball owners, even the more experienced ones. We are often tempted to believe, "Player X has been one of the best players in fantasy so far, so he therefore is guaranteed to remain one of the best the rest of the year."

Going-forward rankings/projections, however, represent the only worthy measures for player valuation.

Let's face it: Past performance is irrelevant, except only in how it influences the player's present and future. We use past stats to generate projections, and from those rankings; it is our duty to sift through the stats that have already been accrued and dismiss, entirely, the ones that don't matter. Just as was the case on April 5, every player's stat sheet is a blank page, from a fantasy-value angle.

The pitfall in this game is to cling too tightly to the numbers of April. Yes, it's a new season, with new roles, new approaches, but the fact remains that several years of data still trumps what is only 25 days' worth of data so far in 2015. It's the main reason that I use going-forward projections -- primarily my own rough set -- as the foundation for the rankings in this space each week.

Still, the deeper we get into the season, the more fantasy owners will lean upon 2015 stat lines. I understand that temptation, but it's the reason some of the most unexpected, positive individual player performances will make those players' rankings below look increasingly out of place.

Here's the key to player valuation: It's your team. Buy-low and sell-high strategies tend to be popular this time of year, as are questions about such candidates. The truth is that buy-low/sell-high players aren't who I tell you they are; they are the players for whom your own opinion resides furthest from mine (and honestly, from a trading standpoint, your trade counterpart).

Let's examine a few such examples on the hitting side, players whose torrid starts might make them either sell-high or stick-with candidates:

Devon Travis His is the quintessential example of the difficult-to-value fantasy hot-starter, a player residing in the "unknown" basket due to his rookie status and middling prospect rankings. This meant his sizzling start is leading to many questions of "Did we all simply underrate this guy?" Still: Travis is batting .356; he has never batted higher than .352 at any single level in any single professional season previously. He's on pace for 46 home runs in 617 plate appearances; he has never hit more than 16 home runs in any previous professional season nor has he had a 617-plate appearance seasonal pace greater than 17 homers. Yes, he plays in a favorable hitters' environment in Toronto; yes, he's surrounded by a productive lineup sure to fuel his RBIs/runs, and yes, he possesses a good contact-hitting profile. But the fact remains that Travis' minor-league profile matters from a going-forward projections -- and rankings -- standpoint. For example, let's take his line from two of the better-known such projection systems:

ZiPS: 104 G, 447 PA, .256/.303/.412, 14 HR, 51 RBIs, 9 SB, 54 R

Steamer: 97 G, 413 PA, .268/.314/.426, 12 HR, 47 RBIs, 9 SB, 52 R

That's a wider range than you'd see for most players, the primary difference a near-2-percent strikeout rate (16.8 percent for ZiPS, 14.9 percent for Steamer), which explains the batting averages. Looking at those projections, as well as both his minor league statistical and scouting profiles, I'd argue that both are fair, though the batting averages might be 10-20 points light. And let's face it, 10-20 points of batting average is roughly the equivalent of an additional, "lucky-bounce" hit approximately every three weeks.

By the way, those projected going-forward stat lines don't condemn Travis as a meaningful mixed-league asset. That is the mistake fantasy owners often make, looking at such a line or his "low" ranking below. To illustrate: Take his lesser projected number in each of the five Rotisserie categories, or .256-12-47-9-52. Care to guess how many middle infield-eligible players managed to reach all five of those thresholds from April 29 forward in 2014? Five: Robinson Cano, Ian Desmond, Josh Harrison, Ian Kinsler and Anthony Rendon.

I'm on board with those of you who believe Travis will make a meaningful fantasy contribution from this point forward. That's not our debate. It's that if you think he'll continue at the pace of even a top-100 overall player, drop me a line; I'd sell him for any member of my top 100 right now, your choice.

Injury-history players like Lorenzo Cain and Joey Votto: It's the players with histories of significant missed time -- especially Votto's, which was more recent -- that tend to be challenging to project. Is it fair to assume either one will miss extended time in 2015, especially since Votto hasn't missed a single Cincinnati Reds inning, while Cain has sat only once (April 20) plus missed six innings of an April 23 contest following an ejection?

You have to consider that neither going-forward projection set referenced above has either player ranked among the top 90 in games played, with playing time possessing a significant -- and oft-overlooked -- influence upon rankings. Still, in Cain's case, consider that in the past 162 Kansas City Royals games (postseason included), he has played in 151, started 140, batted .305/.351/.426 and totaled seven home runs, 67 RBIs, 33 stolen bases and 75 runs scored. Anyone care to guess how many other players have managed at least a .300 batting average and 30 steals in the past calendar year? Two: Jose Altuve and Denard Span.

Votto, meanwhile, has for the entirety of his career been one of the keenest strike-zone judges in baseball, as well as one lacking in platoon (righty/lefty or home/road) splits. Besides the obvious health issues, the only thing that has changed for him is his power: He has a 33.3 percent home run/fly ball rate, which hints that his final number should reside closer to his 18.6 percent career number than the 10.7 that ruined him in that department in 2014. It's a good signal that he's again fully healthy, and at 31 years old he's close enough to his career prime that it's worth taking the chance he'll stay that way.

Buy both -- or, more accurately, don't sell, if you have them.

Productive San Diego Padres outfielders: They're all right-handed. They're all defensive questions. They're all now scheduled for 81 of their 162 games at one of the worst power environments in baseball in Petco Park. And yet, through nearly a month's play, Wil Myers (No. 12 overall), Matt Kemp (19) and Justin Upton (26) all find themselves ranked among the Player Rater's most productive early performers. What in the name of Phil Nevin is going on here?

My preseason rankings -- and most sources' -- had Upton, Kemp and Myers in that order, and easily so. Understandably, their going-forward projections and rankings remain that way, due to Upton's track record and prime-of-career age, Kemp's up-and-down recent career history, and Myers' awful 2014 plus smaller major-league sample. Little has changed in a month, and two things stand out as reasons why Kemp's and Myers' exploits aren't yet enough to significantly move them upward in the rankings: Kemp's BABIP is .394, well above his .352 career number, and his hard-hit average is .146, well beneath his .221 number since 2009. He has also hit 54 percent of his batted balls on the ground, which is a significant increase for him.

Myers, meanwhile, has a disturbingly low 2.1 percent walk rate -- his was 9.1 percent in his first two seasons -- which makes him look like an odd choice to lead off. He's also on pace for 22 stolen bases which, while a promising sign, would exceed his previous single-season professional high by 10. Both outfielders require more evidence before being valued near their current Player Rater spots, but there's a chance that some owners might see the Padres' hot-hitting start as a reason to overpay for either on the trade market.

New ESPN position eligibility

The following players added new position eligibility within the past week. As a reminder, position players need to appear 10 times at a new position to gain in-season eligibility, while pitchers need to make three starts to earn starting-pitching eligibility or five relief appearances to earn relief-pitching eligibility.

Chris Bassitt (RP), Gordon Beckham (3B), Mike Bolsinger (RP), Alberto Callaspo (3B), Eric Campbell (3B), Logan Forsythe (1B), Jason Garcia (RP), Sean Gilmartin (RP), Tanner Roark (RP), Sean Rodriguez (1B), Andrew Romine (3B), Jake Smolinski (OF), Adam Warren (SP).

The following players are within two games of earning new eligibility, with their total games played noted at the listed position: Matt Duffy (3B, 9 games), Hector Gomez (2B, 8 games).

Going-forward rankings: Week 4

Listed below are my updated, going-forward rankings. These are based upon an ESPN standard league of 10 teams and Rotisserie 5x5 scoring. Click here to see these rankings sorted by position.