Mystery Solved: 1990 Colorado Springs Sky Sox

In the CMC set, though, with posed shots taken on the team's photo day, the conditions were controlled and other players typically stayed out of the shot.
Except for the Colorado Springs Sky Sox. Their photo day in May 1990 seemed a little more lax. Players got their photos taken, some more than once. That's because in a couple of the Colorado Springs Sky Sox cards, players accidentally showed up in the background.
On Colby Ward's card, for instance, (featured in February 2012) there appears to be as many as five players way in the background. They're too far away, though, to identify any of them.
There's another player in the background of Jeff Wetherby's card (featured in January 2012), again too far away for identification. Same with Luis Medina and Efrain Valdez.

The question was, who was that player? And did that player have his own card in the CMC set? If not, then that player would get his own feature here. There are a couple instances in the set where photos and players didn't match. That's meant that both players got featured here.
On some of the CMC cards, uniform numbers can be seen. Joe Skalski was No. 27. He appears to be wearing his home jersey. Most, though, are wearing what appears to be their road jersey, numbers on the back, with no numbers on the front.

A check with the team, though, turned up empty. They just didn't have much from their Indians era.
The next place to look was Ebay. People often sell older minor league stuff there. Maybe a scan would even have the answers I sought. Nothing there, at least not in December when I was looking.
But I didn't give up. I kept checking Ebay. And nothing kept coming up.
Awesome.
Maybe the players included their numbers in their signatures?
So I bought it. If nothing else, it would be a cool autographed baseball from the very players I've been featuring here.
It arrived and, what was inside with the ball?

It wasn't a perfect match, though. The ball appears to have been signed late in the season.
By that time, the Sky Sox had a new manager. Bobby Molinaro, whom they'd started the year with and the manager in the CMC set was gone. By this time, managing the team was some guy named Charlie Manuel.
But a lot of the players are there. Medina's still there. He's on the ball. Wetherby's there. He's also on the ball. Same with Skalski, still No. 27.
So, in late August 1990, who was No. 42?
Carl Willis. He was No. 42.
Willis was also there in May for photo day. He was there because he has his own card in the set.

Mystery solved. No extra feature needed.
Awesome.
As for the ball, according to the roster, there are 17 players on the ball who were in the CMC set. Three of them actually represent promotions from AA Canton-Akron, those players appearing with Canton-Akron in the set.

The full list, with links to their features: Beau Allred, Alan Cockrell, Mark Lewis, Ever Magallanes, Tom Magrann, Luis Medina, Troy Neel, Turner Ward, Jeff Wetherby, Jeff Edwards, Mike Curtis, Reese Lambert, Greg McMichael, Rudy Seanez, Joe Skalski, Carl Willis and coach Rick Adair.