Stand a 600-foot "F" next to the Space Needle, and the two structures would spell and approximate the size of the "IF" facing the Seattle Mariners as they contemplate making the playoffs for the first time since a month after 9/11. The "ifs," of course, include the perennials: pitching, hitting, defense, coaching and avoidance of injuries. The predominant variable, however, on the eve of the March 31 home-opener at Safeco Field against Texas, is none of the above. It's whether the promising roster Manager John McLaren has been handed by General Manager Bill Bavasi performs in aggregate at the upper end of players' capabilities. If this happens, the M's will finish ahead of the suddenly pitching-challenged Los Angeles Angels with 100-plus wins and possibly the best prospects in the American League playoffs. If not, not: It's that simple and complicated. Only fools attempt to project player performances, so here, in no particular order, I go: Adrian Beltre. Despite a numb thumb, the third-baseman seems poised for a hyper-productive offensive season to match the miracle-caliber defense he always plays. Beltre turns 29 April 7. It's often thought of as a baseball player's prime age (though Ichiro Suzuki's is 20 to 50 and Randy Johnson's has seemed that long). Most of Beltre's stats have ticked up each of the past two seasons, and even a modest improvement would put him at .290 with 100-plus runs batted in and 30 home runs: an ideal mid-order hitter, unlike: Jose Lopez. He's really just a kid at 24. Yes, his numbers were down last year, but management thinks enough of his upside to stick him in the two hole of the lineup, which would require looking at (and away from) a lot of pitches and batting a bunch with Ichiro on base. It requires patience, leading one to wonder why, then, a more veteran guy shouldn't be tried in this spot, perhaps: Yuniesky Betancourt. The high-potential shortshop during a recent game showed coaches and TV viewers what happens when he gets his pitches. Betancourt had a double and home run, five RBI and three runs scored — was, indeed, his team's offense for the March 27 7-2 win. One could imagine flipping him in the batting order with Lopez: from ninth to second. At the very least, the expectation is that the otherwise Oreck-like shortstop won't sail so many balls away from the target at first base, that being: Richie Sexson. He's tall enough to maybe pose as the exclamation mark next to the "IF" referenced above. If nothing else — and it nearly was nothing last season — Big Richie can grab an errant infield throw for you. Then again, Ron Fairly, at about a foot shorter than Sexson, played credible defensive first base and hit with a lot more consistency than the M's $15 million man. The team's pretty much stuck with Sexson and his lamentably generous contract, although a bad April could send him to the bench, possibly to be replaced by: Brad Wilkerson. Actually the stout lefty (who, coincidentally, looks and comports himself uncannily like Ron Fairly, even sporting the same uniform number 6) was hired to play behind Sexson in right field, though Wilkerson has worked at first base. One worry is that Wilkerson's batting average has dropped about 20 points since he moved to Texas from the National League a couple of years ago. The 30-year-old also gives the M's an all-left-hitting outfield, potentially giving the lineup four lefties when the designated switch-hitter is: Jose Vidro. This isn't so much about Vidro (rhymes with "he slow"), though, as Mike Morse. M's bosses seem to concede begrudgingly (as the McManager did to broadcaster Dave Niehaus before the March 27 game with San Francisco) that the versatile Morse would have been the team's spring-training MVP were there such a thing. Why, then, one wonders, wouldn't management make an effort to try to keep Morse's .500-clip bat in the lineup at least as a platoon DH? We'll see. As I write this Friday afternoon (March 28) it isn't even clear whether Morse has made the team, though he has played left field a few times in place of: Raul Ibañez. The venerable, personable veteran is a key to this team less for what he brings to the game than to his clubhouse presence. He's a prized veteran in the Edgar Martinez tradition who has hit between .280 and .304 during each of the past seven seasons. If he has another one in him, the M's will be justified batting Ibañez third, as is planned, and not one of last year's consistent hitters: Kenji Johjima. He was one of the better-hitting big-league catchers last season, when the M's got lucky with a near career year from back-up Jamie Burke, made easier by the fact that the 36-year-old was playing only his second full season in the bigs. Jeff Clement will open in Tacoma but is considered the club's future starting catcher. The rest of the position-player roster? There ain't much "rest of." One-man band Willie Bloomquist has been bunged up and, while several vied for bench jobs, there wasn't any spring-training competition for starting positions. Nor was there any for starting pitching. Management announced nearly from the outset that the starting five, in order, would be Erik Bedard (the big-acquisition lefty from Baltimore), home-nurtured righty Felix Hernandez, mega-contract get Carlos Silva (R), Jarrod Washburn (L) and Miguel Batista. The latter right-hander had the M's most wins last year with 16. With a youngish bullpen (including all-star closer J.J. Putz and help down on the farm), the M's are said by many to have the most enviable set of arms in the American League. Here again, that's on paper, with a great big "IF," as in: IF only everybody played like Ichiro.