SEATTLE -- While the Mariners still haven¡¯t announced a starter for Tuesday¡¯s game in Texas since sending rookie right-hander Erik Swanson back to Triple-A Tacoma, manager Scott Servais said Saturday the replacement will not be top pitching prospect Justus Sheffield.

Seattle¡¯s No. 1 ranked prospect by MLB Pipeline threw 5 2/3 innings on Friday night in a no-decision for Tacoma in Reno and wouldn¡¯t be ready to make his next start until Wednesday.

Veteran southpaw Tommy Milone is lined up to pitch Tuesday for Tacoma and would appear a prime candidate to be promoted for at least a spot start, having gone 4-2 with a 3.83 ERA in nine outings (eight starts), or the Mariners could go with a bullpen day since they currently have nine relievers.

The 32-year-old Milone would need to be added to the 40-man roster since he initially signed with Seattle on a Minor League deal, but he¡¯s an eight-year MLB veteran with a career mark of 46-37 with a 4.42 ERA in 151 games (131 starts) for five different teams since 2011.

Sheffield pitched a three-inning relief stint behind Yusei Kikuchi¡¯s abbreviated start several weeks ago, but the Mariners aren¡¯t looking to rush him back until he¡¯s ready to stick. The 23-year-old is 1-2 with a 4.38 ERA in eight outings (seven starts) for Tacoma and gave up five hits and three runs with three walks and six strikeouts in his latest start in Reno.

¡°I think when we get to the point where we call Justus up, we¡¯d like to call him up and leave him here and let him go,¡± Servais said. ¡°I don¡¯t want to call him up and give him one or two outings and then go back and forth. He¡¯s working on things right now.¡±

Servais said recent reports on Sheffield have been good as he¡¯s focusing more on his changeup and cautioned not to read too much into the numbers out of the Pacific Coast League.

¡°There¡¯s a lot of positives there,¡± Servais said. ¡°Sometimes getting caught up in the line score in the PCL right now is dangerous. We¡¯re not at the games, so it¡¯s all we can really look at. So you really have to go with the people who are there, giving us reports on the stuff, the command, the hits.

¡°If you look at the numbers in the PCL this year, they are off the chart. They¡¯re playing with the Major League baseball in Triple-A this year and it¡¯s changed the game quite a bit. I think it¡¯s a good thing for the pitchers to not have to make an adjustment when they come to the big leagues with the ball, but the numbers are up dramatically.¡±

Mike Leake is slated to start Monday¡¯s series opener in Arlington and Marco Gonzales is penciled in for Wednesday¡¯s finale, but Swanson was sent down after giving up four homers in his last outing, putting the rookie at 1-5 with an 8.04 ERA in seven games (six starts) in Seattle.

Both Sheffield and Swanson were acquired from the Yankees in the James Paxton trade, along with outfielder Dom Thompson-Williams, who is performing very well in Double-A Arkansas.

Festa returns to Triple-A after impressing skipper

Rookie right-hander Matt Festa, who impressed Servais with his two-inning outing in Friday¡¯s 7-1 loss to the Twins, was optioned back to Tacoma on Saturday to open a spot for starter Wade LeBlanc, who was activated off the injured list.

Festa, ranked by MLB Pipeline as the Mariners' No. 17 prospect, was recalled prior to Friday¡¯s game to bolster Seattle's bullpen and pitched the final two innings, allowing two hits and one run with two strikeouts while throwing 20 strikes in a 28-pitch outing.

¡°I thought Matt Festa threw the ball really well,¡± Servais said. ¡°That was probably the best outing I¡¯ve ever seen Matt have. He¡¯s added some things to his game. Those were a couple bright spots from guys who can really help our bullpen down the road.¡±

Injury updates

? Third baseman Kyle Seager (tendon surgery in left hand) has hit .308 (4-for-13) with a double, three runs and an RBI in his first three rehab games for Tacoma as he works toward a likely return next Saturday when he¡¯s eligible to come off the 60-day disabled list.

? Utility man Dylan Moore reported to Tacoma on Saturday to begin his rehab stint as he recovers from a bruised right wrist. He could be ready to return as soon as Monday in Texas, though the Mariners now have veteran Tim Beckham also working in a utility role since promoting J.P. Crawford to play shortstop.

? Reliever Sam Tuivailala (right Achilles' tendon surgery) also reported to Tacoma to continue his rehab stint after allowing one run in six innings over six outings with Advanced-A Modesto.

Fellow right-hander Gerson Bautista (strained right pec) threw a perfect inning with two strikeouts in his second day of back-to-back outings for Modesto on Friday and will soon be promoted to Tacoma as well. He¡¯s allowed two earned runs in five innings in five appearances.

? Servais said Felix Hernandez (strained right lat muscle) has begun doing rehab work, but yet to pick up a baseball since going on the 10-day IL earlier this week for what is expected to be a 4-6 week layoff.

¡°He¡¯s working out and getting after it really good,¡± Servais said. ¡°I know he wants to get back as quick as he can. The reports are good there. But he¡¯s not throwing yet.¡±