64 Sam Tuivailala RP

Tuivailala (knee) will likely head for a rehab assignment sometime next week according to Cardinals president of baseball operations John Mozeliak, Steve Overbey of MLB.com reports.

Tuivailala headed to the disabled list last Saturday with his knee strain, but it appears his recovery is going well. The right-handed reliever has generated a 4.50 ERA across four innings over four appearances thus far this season.

Tuivailala was placed on the 10-day disabled list with a left knee strain, Joe Trezza of MLB.com reports.

The right-hander last appeared out of the bullpen against the Brewers on Monday, pitching two scoreless innings during his fourth outing of the season. It's unknown whether he sustained the injury during that game or in the last couple days, but Tuivailala will be sidelined until April 20, at the earliest. In a corresponding move, Mike Mayers was recalled from Triple-A Memphis.

Tuivailala fired two scoreless innings in a 5-4 extra-inning loss to the Brewers on Monday, allowing two hits.

Tuivailala had been somewhat uncharacteristically unsteady in his first three appearances of the season, allowing two earned runs on four hits in the two innings he'd worked across that span. That followed a spring in which the 25-year-old right-hander had generated an impressive 1.23 ERA across eight appearances, a sample during which he'd yielded a lone run over 7.1 innings. Tuivailala was similarly effective across a career-high 37 appearances in 2017 -- generating a 2.55 ERA and 1.09 WHIP over 42.2 innings -- so he projects for a similar or greater workload in 2018 if he can consistently replicate that caliber of effort.

Tuivailala's spring ERA remains unblemished across six outings after he fired a scoreless seventh inning in which he allowed a hit and recorded two strikeouts during Sunday's 10-0 Grapefruit League win over the Nationals.

One of manager Mike Matheny's steadiest bullpen options in 2017, Tuivailala has picked right up where he left off. He's racked up 12 strikeouts over just 5.3 exhibition frames while scattering four hits, leaving him poised for another sizable role this season. The Cardinals have plenty of holdover relief options, but the 25-year-old is proving as reliable as any of them during what has been a dominant spring.

Tuivailala fired a scoreless eighth inning in Wednesday's 6-0 loss to the Reds.

The 24-year-old right-hander has generated scoreless efforts in three of his last four trips to the mound and has notched at least one strikeout in five of his last six outings. Tuivailala continues offering some decent strikeout upside overall (29 over 35.1 innings) while also sporting a solid 2.80 ERA and 1.19 WHIP.