Headley, 33, hit .273 (140-for-512) with 30 doubles, one triple, 12 home runs, 61 RBI and 77 runs scored for the Yankees in 2017. The former Padre played parts of eight seasons with San Diego (2007-14) and earned All-Star honors in 2012 after leading the National League with 115 RBI while hitting .286 and setting career highs in hits (173), home runs (31), runs scored (95) and walks (86).
Headley also won the Gold Glove and Silver Slugger Awards in 2012 after leading all Major League third basemen in games played (161) and assists (315) and topped all NL third basemen in home runs, runs scored and walks. Originally acquired by the Padres in the second round of the 2005 First-Year Player Draft, the switch-hitter owns a lifetime .264 (1331-for-5036) average with 271 doubles, 16 triples, 130 home runs, 592 RBI and 635 runs scored in 1,409 games played over parts of 11 Major League seasons.
Mitchell, 26, made 20 appearances (one start) for the Yankees in 2017, going 1-1 with a 5.79 ERA (21 ER, 32.2 IP). He also appeared in 14 games (13 starts) for Triple-A Scranton-Wilkes Barre, going 3-3 with a 3.25 ERA (23 ER, 63.2 IP) with 66-to-13 SO/BB ratio.
Originally selected by the Yankees in the 16th-round of the 2009 First-Year Player Draft, the 6-3, 210-pound right-hander has gone 2-6 with a 4.94 ERA (54 ER, 98.1 IP) in 38 Major League appearances (nine starts) and 30-43 with a 4.16 ERA (294 ER, 635.1 IP) with 584-to-284 SO/BB ratio in 137 minor appearances (131 starts).
The Padres have also acquired infielder Deion Tansel in exchange for infielder Ryan Schimpf.
Tansel, 23, hit .277 (53-for-191) with 11 doubles, two triples, three home runs, 33 RBI, 23 runs scored and seven stolen bases for Single-A Hudson Valley in 2017. Originally selected by Tampa Bay in the 32nd-round of the 2016 First-Year Player Draft, he owns a .280 (83-for-296) average with 17 doubles, two triples, four home runs, 43 RBI and 37 runs scored in 85 minor league games over parts of two seasons.
At the University of Toledo in 2016, Tansel was an All-MAC First-Team selection and also took home MAC Defensive Player of the Year honors for the second consecutive season. The Grand Rapids, Ohio native hit a team-best .327 for Toledo in 2016 with 12 doubles and 29 RBI. Tansel wrapped his Toledo career tied for fourth in UT history with 247 career hits.