Milt came to the Cubs in 1970, having been purchased from the Braves. His career was in the dumps and it was either make it or break it with the Cubs.
He made it, going 51-41 during his 3½ years in Chicago.
The highlight of his time as a Cub was his near-perfect game against the Padres in 1972. I have very clear memories of watching that game in our basement. I was disappointed that he didn't get the perfect game, but not as much as Milt. I think he went to his grave bitter about the walk to Larry Stahl.
In addition to the card above, I have ten others of Milt as a Cub.
Topps has four cards of his as a Cub. He was included in the 1974 set although he was out of baseball in 1974, being released by the Cubs in spring training. He was bitter about that too. He had 99 wins in the NL to go along with his 110 AL wins. He missed by one win of becoming one of just a hand full of pitchers with 100 wins in each league. The Tribune article on his release is here.
This card is Milt as a Cub as a Brave. It's from the 1971 Dell Today set. He's in the Cub book, but obviously is not in a Cubs uniform.
These were in the Season Ticket holders and Giveaway sets from 2013.
This is from the 1973 Jewel set.
The last two are a bit more special.
This is also a 2002 Wrigley Field giveaway and it's been signed.
This Cubs convention card from 1998 was also signed. I've got no idea if the signature is legit or not. Milt was a regular at Cubs Conventions. He settled in the Chicago suburbs after his career ended and was at Wrigley Field often too. He really embraced his Cub-ness even though he was with the Orioles for the longest part of his career.