The Athletics optioned starting pitcher Eric Surkamp to Triple-A Nashville on Thursday. As this is an off day, no corresponding move needs to be announced until Friday.
The move commits the A's to a four-man rotation that includes Rich Hill starting on Saturday. There had been some concern about Hill after he sustained a minor groin strain in his last start on Sunday, but he came through a bullpen session fine and the A's elected to just give him an extra day of rest afforded by Thursday's off day.
To be recalled on Friday
We know that the A's will not be calling up Daniel Coulombe, Max Muncy, Matt McBride, or Zach Neal as all four were optioned May 25 or later and are subject to a 10-day minimum stay in the minor leagues (unless recalled to replace a player going on the disabled list).
An eighth reliever?
If the A's call up an eighth reliever, right-hander J.B. Wendelken is the only eligible choice who is on the 40-man roster. Wendelken allowed five runs and recorded seven outs against the Baltimore Orioles and Boston Red Sox in May. Since returning to Nashville, he has struck out 16 and walked six with a 6.23 ERA in nine appearances.
Wendelken might just be called up for Friday's game. Daniel Coulombe is eligible to be recalled on Saturday and had two scoreless appearances for the A's a couple weeks ago, retiring all 11 batters he faced.
A position player?
The A's could call up an extra position player. With the A's expected to face five consecutive right-handed pitchers between Houston and Milwaukee, Andrew Lambo is a left-handed bat that could give the A's an extra outfielder to give Coco Crisp time off after appearing in 17 consecutive games, his longest streak since appearing in 23 consecutive games at the end of the 2014 season.
Lambo struggled in April for Triple-A Nashville (.215/.282/.354), but since the start of May he has hit .284/.345/.385 with two home runs and five doubles in 119 plate appearances with nine walks and 19 strikeouts.
Like Wendelken, Lambo could just be called up for the one day until Max Muncy is eligible to be recalled on Saturday.
Someone not on the 40-man roster?
The A's actually have two players they can transfer to the 60-day disabled list to create room on the 40-man roster. Mark Canha has not been moved to the 60-day disabled list yet and is out for the rest of the year. Henderson Alvarez is making progress on his return, but it will come after the 60th day of the regular season anyway.
If the A's want an eighth reliever, right-hander Tucker Healy is making a bid for a call up after striking out 33, walking eight, and allowing six earned runs and one home run in 22 1/3 innings, giving him both a FIP and an ERA of 2.42. Left-hander Patrick Schuster has struck out 21, walked seven, and allowed two earned runs (no home runs) in 21 innings, giving him an 0.86 ERA and 3.00 FIP.
While there are a number of position player prospects who have recently started heating up at the plate, I don't think the A's will pull them out of the minor leagues just to act as a fifth (or sixth without the DH in Milwaukee) bench player. I will mention that first baseman-right fielder Matt Olson has hit .262/.355/.467 since the start of May.
How long will the A's have the extra man?
Whoever the extra player is, he's most likely to stay around until the A's activate Sonny Gray from the disabled list. The club expects to activate him on June 10 in Cincinnati, five days after Sunday's rehab start with the Stockton Ports where he will go five innings or 90 pitches. If he's not available by then, the A's don't need a fifth starter until June 14.