Kevin Siegrist, a lefty reliever placed on the Disabled List on July 1 (retroactive to June 30) with mononucleosis, has been activated by the St. Louis Cardinals. In a corresponding roster move, reliever Sam Tuivailala, who joined the Cardinals when Siegrist went to the DL, was demoted to Memphis.
Siegrist has been a major part of the Cardinals' bullpen since 2013, and he threw 32 1/3 innings over the first three months of the 2016 season. He had a 2.78 ERA and although his fielding-independent ERA stands at 4.51, his walk rate is down a full walk per nine innings from his previous career best.
The 23 year-old Tuivailala has had stints in the majors in each of the previous three seasons, and he appeared in three games during his most recent MLB cup of coffee. He surrendered three earned runs on July 3 against the Milwaukee Brewers after facing only three batters, though he fared better in successive appearances against the Pittsburgh Pirates on July 4 and July 6. In AAA in 2016, he has an alarmingly high 5.06 ERA but his 2.99 FIP, assisted greatly by a video game-like 13.5 K/9 over 32 innings, suggests that he is pitching at a higher level than his high ERA suggests.
The activation of Siegrist and demotion of Tuivailala does not come as a huge surprise. The Cardinals have been operating with only Tyler Lyons, also ostensibly the team's long reliever, as its only lefty reliever, and the relatively low-leverage application of Tuivailala suggests what we suspected from the beginning: that he was going to serve as depth. The timing of the initial move to place Siegrist on the Disabled List, whether by design or coincidence, allowed the team to bring him back at an intuitive time: following a four-day break.