The pending return of Carlos Beltran from the disabled list should be a time of joy for all Mets fans. When healthy and rested, Beltran is a dominant player, one of the very best in baseball, and the Mets are a different — and better — team with him in the lineup and in center field.

With Beltran’s return, though, comes a question: What to do with Lastings Milledge and Shawn Green? There’s only one right answer to this question. But that doesn’t mean that this is the answer Willie Randolph is going to give.

To state it plainly, Milledge is a much better ballplayer than Green. He was better as of spring training, he’s been better lately, and he’ll be better over the 48 games remaining in the season. He’s better at the plate, better in the field, and better on the base paths. The Mets are more likely to win with him playing every day than they are with Green. The difference isn’t enormous, but it’s real. Milledge is hitting .303 AVG/.344 OBA/.483 SLG, Green .277/.324/.423. These batting lines fairly represent their abilities, and what can be expected of them over the rest of the season. The difference, over 48 games, works out to about 10 runs, or a win. That doesn’t take defense or baserunning into account, and it’s enough that the wrong choice here could potentially decide the race in the National League East.

Nearly as important, to my mind, is the difference in their styles. Over the last two weeks, Green has been playing well. He’s been one of the few Mets consistently picking up big hits in the clutch, and he’s been making up for a lack of range in the field with his willingness to dive all over right field in search of fly balls. He always plays hard, smart, and within his limits. Still, he’s a lethargic player, with feet of lead, a bat of iron, and a methodical approach at the plate, entirely lacking anything like explosiveness. He may not make many mistakes, but he’s certainly not going to force the enemy to do so.

Milledge, whatever his other problems, cannot be accused of this. If he’s not frantically scurrying around the bases in search of a triple, he’s whacking the ball to the opposite field or racing all over center field. He brings vibrancy and enthusiasm to the field. He’s a Met of the Oliver Perez and Jose Reyes class, rather than the Green and Carlos Delgado class, and that’s a good thing. When the Mets are going right, they strike the right balance between veteran savvy and youthful vigor. When Green, Delgado, Paul Lo Duca, Moises Alou, and Luis Castillo are all on the field, that balance goes awry.

The argument for playing Green over Milledge isn’t nearly as compelling. It is, essentially, that Milledge still has to pay his dues. There are other ways to phrase it. You can, for instance, point out that with Alou and Green on the corners and a weak bench, Milledge is going to get his at bats whether or not he’s the nominal starter. You can even make the point that with the injury-prone and aging Alou in left field, it’s necessary to keep Milledge on the pine so that he can fill in for Alou in left during games as required.

Neither of these claims really holds up. The first doesn’t make any sense. If Milledge is a demonstrably superior player to Green, why wouldn’t you try to maximize his at bats? The second makes even less sense. If Alou needs to come out of a game in the seventh inning and you don’t want Green in left, you can always move Milledge there.

No, the only reason there’s any controversy at all here is because Green is a respected veteran and Milledge has at times behaved badly — though not, one notes, since his return to Shea in July. If Green were a minor league veteran hitting exactly as he’s hitting, and Milledge were Milledge, for better and for worse, Green would be moved to a role as a pinch hitter and spot starter, a role in which he’d help the team. Who wouldn’t rather see Green than Marlon Anderson coming off the bench in the clutch?

This being so, Milledge simply has to start. If the man’s hijinks are unbearable, that may be a perfectly good reason to trade him. It’s not a good reason to not to give him a starting job, though. Those should go to the best players: The point of baseball is to win. Randolph has done an excellent job in Queens over the last few years in large part exactly because he’s understood that. This is no time to get deferential toward a player who’s been a Met for a little over a year now. Everyone knows Milledge is the future, and just as surely that he’s the present, as well. When Beltran returns, the Mets ought to act like they know it, too.

tmarchman@nysun.com