In his first four days in the major leagues, Mike Jacobs, up from Double-A to serve as an emergency catcher for the Mets, didn’t get a single at-bat.

The first time he came to the plate, in Sunday’s game against Washington, he cracked a three-run home run. He was almost sent down after that game, but was instead put in the lineup the next night against Arizona, and took an 0-for-4 collar in that game.

In the next two games, which the Mets won by a combined score of 32-5, he hit went 6-for-11 with three walks, driving in six and scoring seven, becoming the first player in major league history to hit four home runs in his first four games. Might the Mets have found themselves a first baseman?

Count me as a skeptic. There are reasons to think Jacobs might well be a player – someone to class with David Wright, Jose Reyes, Victor Diaz, Jae Seo, and Aaron Heilman – and a vital part of what has suddenly become a stunning corps of young Mets. But Mets fans shouldn’t get ahead of themselves.

First, the good news.

For those who don’t follow the minor leagues very closely, Jacobs is indeed a prospect.

In 2003, while catching at Double-A Binghamton, Jacobs hit .329 BA/.376 OBA/.548 SLG in 407 at-bats. Let the air out of the numbers – Binghamton is a good hitter’s park in a good hitter’s league – and Jacobs was hitting about as well as Jorge Posada is this year.

Catchers who are 22-years-old who hit that well in Double-A tend to end up making a lot of money in baseball.

Last year was a lost season for Jacobs, as he endured shoulder injuries and hit .177 in 96 Triple-A at-bats.

This year, there was good and bad. He was hitting .323/.374/.591 before being called up, but he was doing it while playing first base and he was doing it at Binghamton.

With Diaz learning to play first base at Norfolk, there was no room for Jacobs at Triple-A.

So, Jacobs has some serious weaknesses. He has no real experience above Double-A, he doesn’t field well enough to catch, and he doesn’t have much experience at first. (He played 54 games there for Binghamton this year.)

Jacobs has shown the ability to hit for average and power, but he hasn’t showed great discipline – this year, he walked 35 times against 94 strikeouts in Binghamton, and two years ago the ratio was 28 to 87.

The low walk rate isn’t necessarily a concern – if you can hit .320 you don’t need to walk all that much.

The greater concern is the high ratio of strikeouts to walks, which shows there are some problems in his pitch selection. The strengths of Jacobs are hitting for power and average, and he’s not going to do either for the Mets without being able to lay off high fastballs, off-speed pitches over the outside corner, and other offerings of the sort that he’s going to see in the majors.

The secondary concern is that since he’s probably not going to be hitting .320 in the majors, his relative lack of walks is going to keep his on-base average down, which is a problem for a first baseman – especially one who’s not a great defender.

All this is reason to be skeptical, but is in no way meant to diminish what Jacobs has done, nor what he’s capable of doing. He spent this summer in Double-A for organizational reasons, not because of anything he did wrong. In fact, if not for a poorly timed injury last year, he might have gone north from spring training in Port St. Lucie, Fla., as a big leaguer this past April.

At best, I see Jacobs as very similar to Pittsburgh’s Craig Wilson, another slugger with a poor BB/K ratio who was moved from behind the plate to first base for defensive reasons during Jason Kendall’s reign behind the plate. This year, Wilson’s been on the DL twice with hand injuries.

Last year, Wilson hit .264/.354/.499, and the year before, he hit .262/.360/.511.That’s a reasonable expectation for Jacobs – he’ll hit for a bit more average, but draw a few less walks – and if he achieves that, he’ll be a championship-caliber player.

He could be a bit better than that, and could be a bit worse.

At absolute worst, he’ll be a Jason Phillips-type bench player, with less defense and a lot more power, and that’s also very valuable.

Jacobs’s recent home-run barrage doesn’t augur the second coming of Lou Gehrig, but he’s quite capable of keeping up a hot streak and helping the Mets make the playoffs.

Going forward, he could be anything from an excellent reserve to a near All-Star caliber regular, depending on how he adjusts to the majors.

It sure beats having Todd Zeile around.