A 6-foot-7 contact pitcher who has primarily been a relief workhorse since being the Pirates' second-round selection in the 2007 First-Year Player Draft, Welker was reacquired as a candidate for bullpen depth. He made his brief Major League debut last season, appearing in a pair of late-June games.
Welker, 27, otherwise spent the season with Triple-A Indianapolis, working in 48 games. He allowed only three home runs in 63 innings, with 65 strikeouts versus 31 walks.
Johnson led Indianapolis with 10 wins and the International League with an ERA of 2.39. However, the 29-year-old Minor League veteran has not been able to live up to his billing as a first-round Draft pick by the Red Sox in 2006.
Signed by the Bucs as a Minor League free agent two years ago, Johnson did author a remarkable big league debut on Aug. 18. Taking over at the start of the 11th inning against Arizona in PNC Park, Johnson blanked the D-backs on two singles for five innings before allowing two runs in the 16th to take a 4-2 loss.
Overall, Johnson was 0-2 with a 6.10 ERA in four appearances for the Pirates.
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.