If Bartolo is out of rotation, who should be in?

Bartolo Colon has been a major bust so far for the Braves, and the latest in his string of bad starts Monday might have been enough for the Braves to drop him from the rotation, either by DL'ing him, moving him to the bullpen or designating him for assignment. That decision could come this week before his next scheduled start, which would be Saturday in a doubleheader against the Mets.

(Addendum: The decision, or part of it, came Tuesday when Colon was DL'd for a "left oblique strain.")

So if Colon is dumped -- he knows it could happen -- where might the Braves turn to fill his rotation spot? They'll likely need to add another starter Saturday to get through the doubleheader whether or not they let Colon start one of the games.

Scanning the list of candidates inside the organization, and crossing off the names of some very talented but not-quite-ready younger prospects, the guys who seem promising as possible Colon replacements -- now or after Saturday -- are prospect Sean Newcomb and veteran Kris Medlen.

Since Medlen is only four minor-league starts into a comeback attempt after shoulder issues in 2016, and the Braves have been cautious with him so far to avoid setbacks, I don't know that they'll consider him a possibility. Not yet. (Addenum: manager Brian Snitker, after Tuesday's Colon DL announcement, said Medlen getting close but not quite ready to consider as a replacement. Here's the story on that.)

The Braves could go the safer route and bring back Matt Wisler, who was part of the rotation for most of 2015-2016 but has been used only as reliever this season in two major league stints and has a 5.01 ERA in seven Triple-A starts. I can hear the groans from much of Braves Country as you read that sentence.

And so, Newcomb seems like the guy to go to if the Braves want to aim high and see whether one of their vaunted prospects is ready for the challenge. He's not on the 40-man roster, but the Braves are only at 38 so they could add him without having to drop anyone from the 40-man if they decide they want to.

That’s unless the Braves decide that Medlen is ready -- which seems unlikely this soon -- or unless general manager John Coppolella makes a move between now and Saturday to acquire a starter via trade or sign a starter off the scrap heap, someone who’d been waived or went unsigned. For obvious reasons, the latter option would probably not be attractive to many inside or outside the organization, and the trade markets really won’t start heating up for another couple of weeks or more.

So, let’s focus on Newcomb a moment. A big, imposing, hard-throwing left-hander who turns 24 next week, Newcomb is 3-3 with a 2.97 ERA in 11 starts at Triple-A Gwinnett with 74 strikeouts and 33 walks in 54 2/3 innings.

The walks continue to be problematic and contribute to his not going deep into games, but he’s allowed just three home runs and has been dominant in several starts, most notably an 11-strikeout, one-hit, two-walk, seven-inning performance April 30 in his fourth start of the season.

Newcomb was a first-round draft selection -- 15th overall pick – in 2014 by the Angels, who traded him to the Braves as a key piece in the November 2015 deal that sent Platinum Glove shortstop Andrelton Simmons to Anaheim. (After watching Simmons do his thing last week against the Braves, including a home run, it'd be nice to see some return from that trade about now, wouldn't it?)

Newcomb impressed in a couple of major league spring training games this year, showing flashes of huge potential that made him one of the top 25 prospects in baseball prior to the 2016 season. (He slipped after an erratic 2016 season but still was ranked as high as No. 44 by Baseball Prospectus entering this season.)

Who are the other in-house possibilities, you ask? How about Lucas Sims? Or maybe Aaron Blair? And what’s wrong with Wisler?

Let’s consider those possibilities and why a couple of them seem unlikely.

While Colon was getting knocked around Monday night by the Phillies, Sims was giving up six earned runs, seven hits and two homers in five innings of a loss to the Norfolk Tides, giving him an 0-3 record and 8.38 ERA, .321 opponents’ average and 1.003 opponents’ OPS in his past four starts at Gwinnett.

It’s been a confounding time for Sims, 23, a former Brookwood High School standout who began the season on such an impressive roll that he was being considered for next-man-up status by team officials if and when the Braves needed a starter.

Sims’ slump began immediately after the former first-round draft pick went 4-0 with a 2.16 ERA, .171 opponents’ average and .495 opponents’ OPS in his first seven starts, with 42 strikeouts and nine walks in 41 2/3 innings. In the past four starts, he had 20 strikeouts with 10 walks in 19 1/3 innings.

Wisler has worked as a starter at Triple-A this season but strictly as a reliever in two major league stints, posting a 7.00 ERA in nine innings of two major league games while allowing nine hits and three walks with three strikeouts in nine innings. As a member of the Braves’ starting rotation for most of the 2015-2016 seasons, he went 15-21 with a 4.88 ERA in 47 games (45 starts). Team officials later determined that Wisler probably was rushed to the majors before he was entirely ready.

Wisler’s Triple-A work this season has been disappointing: He is 1-4 with a 5.01 ERA in seven starts at Gwinnett, with 50 hits (four homers), 11 walks and 29 strikeouts in 41 1/3 innings. He was a little better in his most recent start Saturday at Gwinnett, allowing six hits and two runs in five innings a day after being optioned back to Triple-A.

In his last last major league appearance May 28 at San Francisco, Wisler pitched two scoreless innings with no hits or walks. He’s scheduled to make his next start Friday for Gwinnett, so the timing would at least work if the Braves wanted to have him start instead in Saturday’s doubleheader against the Mets.

Which brings us to Blair. He, too, has not handled Triple-A competition the way the Braves hoped he would after getting 15 major league starts a year ago. He’s just 3-3 with a 5.40 ERA in nine starts at Gwinnett and was on the seven-day disabled list before being activated to start Tuesday night (which would put him on short rest Saturday anyway, so basically that rules him out). He has continued to be undermined by inconsistency and control issues – he has 25 walks with 32 strikeouts in 43 1/3 innings.

A year ago, Blair struggled to a 2-7 record and 7.85 ERA in 15 major league starts. The Braves thought he, like Wisler, was probably rushed to the majors before he was ready. That situation was one they hoped to avoid with any young pitchers this season by signing the two over-40 starters and former Cy Young Award winners, Colon and knuckleballer R.A. Dickey, and by trading for left-hander Jaime Garcia with one year left in his contract.

So far, only Garcia has worked out the way the Braves envisioned, and Colon has been so bad that the Braves are likely to dip down to the minors to find a replacement if they don’t move quickly to acquire one from outside the organization, of which the pickings seem a bit slim right now. But, hey, Coppy has surprised us before with a move seemingly pulled from his hat.

Stay tuned.

• This classic from Sinatra seems appropriate today.

"THE SEPTEMBER OF MY YEARS" by Frank Sinatra

One day you turn around and it's summer

Next day you turn around and it's fall

And the springs and the winters of a lifetime

Whatever happened to them all?

As a man who has always had the wand'ring ways

Now I'm reaching back for yesterdays

'Til a long-forgotten love appears

And I find that I'm sighing softly as I near

September, the warm September of my years