As much as the Mets are wary of trading from their potential starting pitching depth, general manager Sandy Alderson is open to the proposition. In an attempt to acquire position players, the Mets will listen if teams ask about the likes of Robert Gsellman, Seth Lugo and Rafael Montero. “We have essentially the same depth today as we had last season and we ran through it pretty quickly,” Alderson said Wednesday at the general managers’ meetings. “But certainly 2018 is going to be predicated upon the health of our pitching staff and if we assume the majority of those pitchers will be healthy, and beyond assuming we’re doing everything we can in the offseason to ensure that, but if we are able to it’s possible we will trade somebody from out of that group. “But I want to emphasize that we thought we had quite a bit of depth last year and ended up with none, so we do have to be careful about that.” The Mets saw improvement from Montero in spurts last season, but aren’t ready to insert the right-hander into the rotation.