Kelly, 26, was acquired in a trade with the St. Louis Cardinals in 2018 and had a breakout year in 2019, finishing with a .245 batting average and 18 homers. He was slightly disappointing in 2020, hitting .221 with five homers.
Weaver, 27, was acquired from the Cardinals in the same trade as Kelly and looked like a future star in 2019 with a 2.94 ERA in 12 starts before injuries derailed his season. The right-hander struggled badly in 2020, finishing with a 1-9 record and 6.58 ERA.
Smith, 29, came to the D-backs in a mid-season trade with the Marlins. The lefty had a 2.45 ERA in 11 innings after the deal and is expected to contend for a spot in the starting rotation this spring.