At the end of last season, the Mets had six major league starters, ranging from a perennial Cy Young candidate to a posse of average innings-eaters: Pedro Martinez, Tom Glavine, Jae Seo, Kris Benson, Steve Trachsel, and Victor Zambrano. They also had Aaron Heilman, whose superb showing in relief and background as a starter made many think he should be inserted into the rotation; Yusmeiro Petit, a top prospect who looked like he would be ready for Shea by mid-summer; and Alay Soler, a Cuban mystery man of whom general manager Omar Minaya is said to think a great deal.

Offsetting this was a lack of relief pitching. Even after signing closer Billy Wagner, the team lacked dependable set-up men past Heilman (who obnoxiously demanded to either be allowed to start or traded after a good showing in winter ball), and there were few, if any, worth having on the market.

Setting aside any quibbles over individual deals – regular readers know I was appalled by the deal that shipped Seo out of town, and by the inclusion of Petit in the trade that brought Carlos Delgado to town – Minaya seems to have pulled off a nice trick.

As it stands, the Mets have four credible starters (Martinez,Glavine,Trachsel, and Zambrano),which is more than most teams. They also have Heilman, who could easily turn out to be the secondbest starter on the team. They have Duaner Sanchez and Jorge Julio,who to say the least, have their flaws but are more than worth gambling on as set-up men. And they also have John Maine, acquired in the deal that shipped Benson to Baltimore, and who has a chance to be a lot better than almost anyone thinks.

Maine, who will turn 25 in May, isn’t generally considered a great prospect. Last year, Baseball America listed him as the sixth-best prospect in a weak Baltimore system, and this year he didn’t even rate in the top 10. His fastball tops out at around 90 mph, and while he throws three other pitches, he doesn’t have the kind of command with them that you’d like to see in a relatively soft tossing righty. In 43 2/3 major league innings, he sports a 6.60 ERA, with more walks than strikeouts.

For all that, he has his strengths. His minor league ERA is 2.75, with an excellent 384/104 strikeout/walk ratio and 19 home runs allowed in 337 2/3 innings. Even last year, when he ran up a 6-11, 4.56 ERA record in a decent pitcher’s park at Triple-A Ottawa, his K/BB ratio was around 3/1, with around one home run per game. Statistically, he’s actually a good bet to outperform Benson this year. I certainly don’t think he will, but it also wouldn’t surprise me, and the difference between the two pitchers is a lot less than the $5 million difference in their salaries would make you think, more a matter of experience and the kind of polish that a quality catcher and pitching coach can impart to a sufficiently eager young pitcher than anything else.

Baseball America points to his lack of control of the inside fastball as a failing, for instance, something backed up by his home run rate. But it’s not too much to imagine that the spacious Shea outfield and the two Hall of Famers on the staff, both of whom play chin music, might be able to help him with that.

More than Maine’s specific virtues or flaws, though, he represents depth. If Heilman fails or Trachsel gets hurt, he’s a big league ready option with a real chance to settle in as a no. 4 starter and set his family up for life. That’s what the Mets lost with the Seo and Petit trades, and that they got some back makes Minaya’s moves, in the aggregate, defensible.

After all, he didn’t convert the surplus of starters into nothing – he turned it into hard-throwing relievers with specific weaknesses that can be compensated for. Sanchez can’t get lefties out, but he’s exceptionally durable, and still young enough to improve; if he’s spotted well, he could be a Turk Wendell-type asset.

Julio has a 99-mph fastball and the bit of control that would lead to him giving up fewer home runs away from being Armando Benitez. Far better to pick up a pitcher of this class than a Mike Stanton-type.

Minaya is gambling, there’s no doubt about that. If Seo and Petit pitch to their potential, Julio and Sanchez don’t throw well, and Heilman implodes, this winter could look like a disaster – at least as far as the pitching is concerned. But he’s also put the team in position to run out the kind of balanced, deep rotation and bullpen that win pennants, and left the team some options should everything not work out exactly according to plan. It’s a risky scheme, and a far sight better than sitting on a pile of average pitchers when you can only start five.

tmarchman@nysun.com