1. Mario Valdez, Chicago White Sox, July 2, 1997.
The White Sox roster at the time had no backup infielders other than Valdez, a 1st baseman by trade. Valdez pinch-hit for 3B Chris Snopek in the 8th inning and stayed in for the 9th, but did not field a ball. Valdez would be demoted 2 days later to make room for Norberto Martin, a utility infielder who had been on the disabled list.
Regular 3B Mike Pagliarulo was out with a hamstring injury. In the August 29 game, Mattingly started at 1st base, but was moved to 3rd after a 6-run, pinch-hitter-filled 5th inning cut the Mariners’ lead to 12-11. In that inning, starting shortstop Mike Fischlin was pinch-hit for, necessitating that starting 3B Wayne Tolleson move to short. Mattingly, who had never played a game at 3rd as a professional, played flawlessly, with 6 assists, including one that started a double play, in the final 5 innings, as the Yankees won 13-12.
Mattingly started the next game at 3rd. Said Yankee manager Lou Pinella, “Don’t look at me like I’m crazy, I need offense.” Mattingly would make an error on the first play of the game, but would quickly make up for it by turning a 5-4-3 double play on the next. After 5 innings at 3rd, which saw 3 Mariner bunt attempts (one a base hit, one a successful sacrifice, and one a failed sacrifice) and 0 Mariner runs, Mattingly was moved to 1st.
Mattingly would play at 1st in the second game of the August 30 doubleheader, but was returned to 3rd for the August 31 series finale. He played well, with 4 assists, but the Yankees lost 6-2.
On September 1, as major league rosters expanded to 40 players, the Yankees called up infielders Bryan Little and Leo Hernandez from Columbus, ending Mattingly’s brief stint as a third baseman.
3. Terry Francona, Montreal Expos, October 6, 1985
It was the last day of the 1985 regular season, and both the Mets and Expos had been eliminated in the NL East. In the top of the 4th inning, Expos starting shortstop Hubie Brooks singled in Mitch Webster for his 100th RBI of the season, and was promptly pinch-run for by the wonderfully-named Razor Shines (Razor was actually his middle name, but why quibble?). In the bottom of the 4th, starting 3B Fred Manrique shifted to shortstop, and Francona replaced Shines at 3rd. Francona made 3 assists in his 4 innings at 3rd, and was himself replaced by Vance Law in the 8th inning, as the Expos hung on to win 2-1.